From d940161a3e36a03739d14dc6e4561c90e9b123ae Mon Sep 17 00:00:00 2001
From: Stegmujo <johannesst@gmx.de>
Date: Mon, 29 Aug 2022 12:15:58 +0200
Subject: [PATCH] Add further nodes

Related code:
https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/services/texvcjs/+/fb56991251b8889b554fc42ef9fe4825bc35d0ed/lib/nodes/

Bug: T312528
Change-Id: I8bd30bc45d2c23214b317ca0c04aa8e7d6a2da33
---
 src/TexVC/Nodes/Big.php                       |  35 +++++
 src/TexVC/Nodes/Box.php                       |  35 +++++
 src/TexVC/Nodes/ChemFun2u.php                 |  38 +++++
 src/TexVC/Nodes/ChemWord.php                  |  35 +++++
 src/TexVC/Nodes/Curly.php                     |  36 +++++
 src/TexVC/Nodes/Declh.php                     |  70 +++++++++
 src/TexVC/Nodes/Dollar.php                    |  24 +++
 src/TexVC/Nodes/Fun1.php                      |  74 ++++++++++
 src/TexVC/Nodes/Fun1nb.php                    |  20 +++
 src/TexVC/Nodes/Fun2.php                      |  82 +++++++++++
 src/TexVC/Nodes/Fun2nb.php                    |  20 +++
 src/TexVC/Nodes/Literal.php                   |   3 +-
 src/TexVC/Nodes/TexArray.php                  | 139 ++++++++++++++++++
 src/TexVC/Nodes/TexNode.php                   |  10 +-
 src/TexVC/Nodes/UQ.php                        |  27 ++++
 tests/phpunit/unit/TexVC/Nodes/BigTest.php    |  49 ++++++
 tests/phpunit/unit/TexVC/Nodes/BoxTest.php    |  49 ++++++
 .../unit/TexVC/Nodes/ChemFun2uTest.php        |  43 ++++++
 .../phpunit/unit/TexVC/Nodes/ChemWordTest.php |  44 ++++++
 tests/phpunit/unit/TexVC/Nodes/CurlyTest.php  |  72 +++++++++
 tests/phpunit/unit/TexVC/Nodes/DeclhTest.php  |  78 ++++++++++
 tests/phpunit/unit/TexVC/Nodes/DollarTest.php |  59 ++++++++
 tests/phpunit/unit/TexVC/Nodes/Fun1Test.php   |  95 ++++++++++++
 tests/phpunit/unit/TexVC/Nodes/Fun1nbTest.php |  44 ++++++
 tests/phpunit/unit/TexVC/Nodes/Fun2Test.php   |  52 +++++++
 tests/phpunit/unit/TexVC/Nodes/Fun2nbTest.php |  44 ++++++
 .../phpunit/unit/TexVC/Nodes/TexArrayTest.php |  77 ++++++++++
 tests/phpunit/unit/TexVC/Nodes/UQTest.php     |  45 ++++++
 28 files changed, 1396 insertions(+), 3 deletions(-)
 create mode 100644 src/TexVC/Nodes/Big.php
 create mode 100644 src/TexVC/Nodes/Box.php
 create mode 100644 src/TexVC/Nodes/ChemFun2u.php
 create mode 100644 src/TexVC/Nodes/ChemWord.php
 create mode 100644 src/TexVC/Nodes/Curly.php
 create mode 100644 src/TexVC/Nodes/Declh.php
 create mode 100644 src/TexVC/Nodes/Dollar.php
 create mode 100644 src/TexVC/Nodes/Fun1.php
 create mode 100644 src/TexVC/Nodes/Fun1nb.php
 create mode 100644 src/TexVC/Nodes/Fun2.php
 create mode 100644 src/TexVC/Nodes/Fun2nb.php
 create mode 100644 src/TexVC/Nodes/TexArray.php
 create mode 100644 src/TexVC/Nodes/UQ.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/BigTest.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/BoxTest.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/ChemFun2uTest.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/ChemWordTest.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/CurlyTest.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/DeclhTest.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/DollarTest.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/Fun1Test.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/Fun1nbTest.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/Fun2Test.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/Fun2nbTest.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/TexArrayTest.php
 create mode 100644 tests/phpunit/unit/TexVC/Nodes/UQTest.php

diff --git a/src/TexVC/Nodes/Big.php b/src/TexVC/Nodes/Big.php
new file mode 100644
index 000000000..ac6fc63fc
--- /dev/null
+++ b/src/TexVC/Nodes/Big.php
@@ -0,0 +1,35 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class Big extends TexNode {
+
+	/** @var string */
+	private $fname;
+	/** @var string */
+	private $arg;
+
+	public function __construct( string $fname, string $arg ) {
+		parent::__construct( $fname, $arg );
+		$this->fname = $fname;
+		$this->arg = $arg;
+	}
+
+	public function inCurlies() {
+		return $this->render();
+	}
+
+	public function render() {
+		return '{' . $this->fname . ' ' . $this->arg . '}';
+	}
+
+	public function extractIdentifiers( $args = null ) {
+		return [];
+	}
+
+	public function name() {
+		return 'BIG';
+	}
+}
diff --git a/src/TexVC/Nodes/Box.php b/src/TexVC/Nodes/Box.php
new file mode 100644
index 000000000..93ee56ac9
--- /dev/null
+++ b/src/TexVC/Nodes/Box.php
@@ -0,0 +1,35 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class Box extends TexNode {
+
+	/** @var string */
+	private $fname;
+	/** @var string */
+	private $arg;
+
+	public function __construct( string $fname, string $arg ) {
+		parent::__construct( $fname, $arg );
+		$this->fname = $fname;
+		$this->arg = $arg;
+	}
+
+	public function inCurlies() {
+		return $this->render();
+	}
+
+	public function render() {
+		return '{' . $this->fname . '{' . $this->arg . '}}';
+	}
+
+	public function extractIdentifiers( $args = null ) {
+		return [];
+	}
+
+	public function name() {
+		return 'BOX';
+	}
+}
diff --git a/src/TexVC/Nodes/ChemFun2u.php b/src/TexVC/Nodes/ChemFun2u.php
new file mode 100644
index 000000000..f6c61748a
--- /dev/null
+++ b/src/TexVC/Nodes/ChemFun2u.php
@@ -0,0 +1,38 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class ChemFun2u extends TexNode {
+
+	/** @var string */
+	private $fname;
+	/** @var TexNode */
+	private $left;
+	/** @var TexNode */
+	private $right;
+
+	public function __construct( string $fname, TexNode $left, TexNode $right ) {
+		parent::__construct( $fname, $left, $right );
+		$this->fname = $fname;
+		$this->left = $left;
+		$this->right = $right;
+	}
+
+	public function inCurlies() {
+		return $this->render();
+	}
+
+	public function render() {
+		return $this->fname . $this->left->inCurlies() . '_' . $this->right->inCurlies();
+	}
+
+	public function extractIdentifiers( $args = null ) {
+		return [];
+	}
+
+	public function name() {
+		return 'CHEM_FUN2u';
+	}
+}
diff --git a/src/TexVC/Nodes/ChemWord.php b/src/TexVC/Nodes/ChemWord.php
new file mode 100644
index 000000000..5caed52f2
--- /dev/null
+++ b/src/TexVC/Nodes/ChemWord.php
@@ -0,0 +1,35 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class ChemWord extends TexNode {
+
+	/** @var TexNode */
+	private $left;
+	/** @var TexNode */
+	private $right;
+
+	public function __construct( TexNode $left, TexNode $right ) {
+		parent::__construct( $left, $right );
+		$this->left = $left;
+		$this->right = $right;
+	}
+
+	public function inCurlies() {
+		return $this->render();
+	}
+
+	public function render() {
+		return $this->left->render() . $this->right->render();
+	}
+
+	public function extractIdentifiers( $args = null ) {
+		return [];
+	}
+
+	public function name() {
+		return 'CHEM_WORD';
+	}
+}
diff --git a/src/TexVC/Nodes/Curly.php b/src/TexVC/Nodes/Curly.php
new file mode 100644
index 000000000..6e1d7d2a6
--- /dev/null
+++ b/src/TexVC/Nodes/Curly.php
@@ -0,0 +1,36 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class Curly extends TexNode {
+
+	/** @var TexArray */
+	private $arg;
+
+	public function __construct( TexArray $arg ) {
+		parent::__construct( $arg );
+		$this->arg = $arg;
+	}
+
+	public function render() {
+		return $this->arg->inCurlies();
+	}
+
+	public function inCurlies() {
+		return $this->render();
+	}
+
+	public function extractSubscripts() {
+		return $this->arg->extractSubscripts();
+	}
+
+	public function getModIdent() {
+		return $this->arg->getModIdent();
+	}
+
+	public function name() {
+		return 'CURLY';
+	}
+}
diff --git a/src/TexVC/Nodes/Declh.php b/src/TexVC/Nodes/Declh.php
new file mode 100644
index 000000000..0b6773c8a
--- /dev/null
+++ b/src/TexVC/Nodes/Declh.php
@@ -0,0 +1,70 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class Declh extends TexNode {
+
+	/** @var string */
+	private $fname;
+	/** @var TexArray */
+	private $arg;
+
+	public function __construct( string $fname, TexArray $arg ) {
+		parent::__construct( $fname, $arg );
+		$this->fname = $fname;
+		$this->arg = $arg;
+	}
+
+	public function inCurlies() {
+		return $this->render();
+	}
+
+	public function render() {
+		return '{' . $this->fname . ' ' . $this->arg->inCurlies() . '}';
+	}
+
+	public function extractIdentifiers( $args = null ) {
+		if ( $args == null ) {
+			$args = [ $this->arg ];
+		}
+
+		$identifier = parent::extractIdentifiers( $args );
+		if ( isset( $identifier[0] ) ) {
+			return [ implode( '', $identifier ) ];
+		}
+		return $identifier;
+	}
+
+	public function extractSubscripts() {
+		$f = $this->fname;
+		// @see
+		// http://tex.stackexchange.com/questions/98406/which-command-should-i-use-for-textual-subscripts-in-math-mode
+		// cf https://phabricator.wikimedia.org/T56818 a is always RM
+		// for f there are only four cases
+		switch ( $f ) {
+			case '\\rm':
+				$f = '\\mathrm';
+				break;
+			case '\\it':
+				$f = '\\mathit';
+				break;
+			case '\\cal':
+				$f = '\\mathcal';
+				break;
+			case '\\bf':
+				$f = '\\mathbf';
+		}
+
+		$x = $this->arg->extractSubscripts();
+		if ( isset( $x[0] ) ) {
+			return [ $f . '{' . $x . '}' ];
+		}
+		return parent::extractSubscripts();
+	}
+
+	public function name() {
+		return 'DECLh';
+	}
+}
diff --git a/src/TexVC/Nodes/Dollar.php b/src/TexVC/Nodes/Dollar.php
new file mode 100644
index 000000000..bfd20eb7f
--- /dev/null
+++ b/src/TexVC/Nodes/Dollar.php
@@ -0,0 +1,24 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class Dollar extends TexNode {
+
+	public function __construct( TexArray $value ) {
+		parent::__construct( $value );
+	}
+
+	public function render() {
+		return '$' . parent::render() . '$';
+	}
+
+	public function extractIdentifiers( $args = null ) {
+		return [];
+	}
+
+	public function name() {
+		return 'DOLLAR';
+	}
+}
diff --git a/src/TexVC/Nodes/Fun1.php b/src/TexVC/Nodes/Fun1.php
new file mode 100644
index 000000000..403bf9f5e
--- /dev/null
+++ b/src/TexVC/Nodes/Fun1.php
@@ -0,0 +1,74 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+use MediaWiki\Extension\Math\TexVC\TexUtil;
+
+class Fun1 extends TexNode {
+
+	/** @var string */
+	protected $fname;
+	/** @var TexNode */
+	protected $arg;
+	/** @var TexUtil */
+	private $tu;
+
+	public function __construct( string $fname, TexNode $arg ) {
+		parent::__construct( $fname, $arg );
+		$this->fname = $fname;
+		$this->arg = $arg;
+		$this->tu = new TexUtil();
+	}
+
+	public function inCurlies() {
+		return $this->render();
+	}
+
+	public function render() {
+		return '{' . $this->fname . ' ' . $this->arg->inCurlies() . '}';
+	}
+
+	public function extractIdentifiers( $args = null ) {
+		if ( $args == null ) {
+			$args = [ $this->arg ];
+		}
+		$letterMods = array_keys( $this->tu->getBaseElements()['is_letter_mod'] );
+		if ( in_array( $this->fname, $letterMods ) ) {
+			$ident = $this->arg->getModIdent();
+			if ( !isset( $ident[0] ) ) {
+				return parent::extractIdentifiers( $args );
+			}
+			// in difference to javascript code: taking first element of array here.
+			return [ $this->fname . '{' . $ident[0] . '}' ];
+
+		} elseif ( array_key_exists( $this->fname, $this->tu->getBaseElements()['ignore_identifier'] ) ) {
+			return [];
+		}
+
+		return parent::extractIdentifiers( $args );
+	}
+
+	public function extractSubscripts() {
+		return $this->getSubs( $this->arg->extractSubscripts() );
+	}
+
+	public function getModIdent() {
+		return $this->getSubs( $this->arg->getModIdent() );
+	}
+
+	private function getSubs( $subs ) {
+		$letterMods = array_keys( $this->tu->getBaseElements()['is_letter_mod'] );
+
+		if ( isset( $subs[0] ) && in_array( $this->fname, $letterMods ) ) {
+			// in difference to javascript code: taking first element of array here.
+			return [ $this->fname . '{' . $subs[0] . '}' ];
+		}
+		return [];
+	}
+
+	public function name() {
+		return 'FUN1';
+	}
+}
diff --git a/src/TexVC/Nodes/Fun1nb.php b/src/TexVC/Nodes/Fun1nb.php
new file mode 100644
index 000000000..e6976b112
--- /dev/null
+++ b/src/TexVC/Nodes/Fun1nb.php
@@ -0,0 +1,20 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class Fun1nb extends Fun1 {
+
+	public function name() {
+		return 'FUN1nb';
+	}
+
+	public function inCurlies() {
+		return '{' . $this->render() . '}';
+	}
+
+	public function render() {
+		return $this->fname . ' ' . $this->arg->inCurlies() . ' ';
+	}
+}
diff --git a/src/TexVC/Nodes/Fun2.php b/src/TexVC/Nodes/Fun2.php
new file mode 100644
index 000000000..f9febc9af
--- /dev/null
+++ b/src/TexVC/Nodes/Fun2.php
@@ -0,0 +1,82 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class Fun2 extends TexNode {
+
+	/** @var string */
+	protected $fname;
+	/** @var TexNode */
+	protected $arg1;
+	/** @var TexNode */
+	protected $arg2;
+
+	public function __construct( string $fname, TexNode $arg1, TexNode $arg2 ) {
+		parent::__construct( $fname, $arg1, $arg2 );
+		$this->fname = $fname;
+		$this->arg1 = $arg1;
+		$this->arg2 = $arg2;
+	}
+
+	public function inCurlies() {
+		return $this->render();
+	}
+
+	public function render() {
+		return '{' . $this->fname . ' ' . $this->arg1->inCurlies() . $this->arg2->inCurlies() . '}';
+	}
+
+	public function extractIdentifiers( $args = null ) {
+		if ( $args == null ) {
+			$args = [ $this->arg1, $this->arg2 ];
+		}
+		return parent::extractIdentifiers( $args );
+	}
+
+	public function name() {
+		return 'FUN2';
+	}
+}
+
+/**
+ * 'use strict';
+ * const TexNode = require('./texnode');
+ * const assert = require('assert');
+ *
+ * class Fun2 extends TexNode {
+ * constructor(fname, arg1, arg2) {
+ * assert.strictEqual(
+ * arguments.length,
+ * 3,
+ * 'Incorrect number or arguments');
+ * assert.ok(
+ * (fname instanceof String || typeof fname === 'string') &&
+ * arg1 instanceof TexNode,
+ * arg2 instanceof TexNode,
+ * 'Incorrect argument type');
+ * super(fname, arg1, arg2);
+ * this.fname = fname;
+ * this.arg1 = arg1;
+ * this.arg2 = arg2;
+ * }
+ *
+ * inCurlies() {
+ * return this.render();
+ * }
+ *
+ * render() {
+ * return '{' + this.fname +
+ * ' ' + this.arg1.inCurlies() +
+ * this.arg2.inCurlies() + '}';
+ * }
+ *
+ * extractIdentifiers(args = [this.arg1, this.arg2]) {
+ * return super.extractIdentifiers(args);
+ * }
+ * get name() {
+ * return 'FUN2';
+ * }
+ * }
+ */
diff --git a/src/TexVC/Nodes/Fun2nb.php b/src/TexVC/Nodes/Fun2nb.php
new file mode 100644
index 000000000..d9dbbc18c
--- /dev/null
+++ b/src/TexVC/Nodes/Fun2nb.php
@@ -0,0 +1,20 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class Fun2nb extends Fun2 {
+
+	public function name() {
+		return 'FUN2nb';
+	}
+
+	public function inCurlies() {
+		return '{' . $this->render() . '}';
+	}
+
+	public function render() {
+		return $this->fname . ' ' . $this->arg1->inCurlies() . $this->arg2->inCurlies();
+	}
+}
diff --git a/src/TexVC/Nodes/Literal.php b/src/TexVC/Nodes/Literal.php
index a504c7cd1..f5930d41d 100644
--- a/src/TexVC/Nodes/Literal.php
+++ b/src/TexVC/Nodes/Literal.php
@@ -19,7 +19,7 @@ class Literal extends TexNode {
 		$tu = new TexUtil();
 		$this->literals = array_keys( $tu->getBaseElements()['is_literal'] );
 		$this->extendedLiterals = $this->literals;
-		array_push( $this->extendedLiterals, [ '\\infty', '\\emptyset' ] );
+		array_push( $this->extendedLiterals,  '\\infty', '\\emptyset' );
 	}
 
 	public function extractIdentifiers( $args = null ) {
@@ -39,7 +39,6 @@ class Literal extends TexNode {
 
 	private function getLiteral( $lit, $regexp ) {
 		$s = trim( $this->arg );
-
 		if ( preg_match( $regexp, $s ) == 1 ) {
 			return [ $s ];
 		} elseif ( in_array( $s, $lit ) ) {
diff --git a/src/TexVC/Nodes/TexArray.php b/src/TexVC/Nodes/TexArray.php
new file mode 100644
index 000000000..21da07d45
--- /dev/null
+++ b/src/TexVC/Nodes/TexArray.php
@@ -0,0 +1,139 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+use InvalidArgumentException;
+
+class TexArray extends TexNode {
+
+	public function __construct( ...$args ) {
+		$nargs = [];
+		self::checkInput( $args );
+
+		foreach ( $args as &$arg ) {
+			if ( $arg != null ) {
+				array_push( $nargs, $arg );
+			}
+		}
+		parent::__construct( ...$args );
+	}
+
+	public function inCurlies() {
+		if ( isset( $this->args[0] ) && count( $this->args ) == 1 ) {
+			return $this->args[0]->inCurlies();
+		} else {
+			return '{' . $this->render() . '}';
+		}
+	}
+
+	public function extractSubscripts() {
+		$y = [];
+
+		foreach ( $this->args as $x ) {
+			$y = array_merge( $y, $x->extractSubscripts() );
+		}
+		if ( isset( $this->args[0] ) && ( count( $this->args ) == count( $y ) ) ) {
+			return implode( '', $y );
+		}
+		return [];
+	}
+
+	public function extractIdentifiers( $args = null ) {
+		if ( $args == null ) {
+			$args = $this->args;
+		}
+		$list = parent::extractIdentifiers( $args );
+		$outpos = 0;
+		$offset = 0;
+		$int = 0;
+
+		for ( $inpos = 0; $inpos < count( $list ); $inpos++ ) {
+			$outpos = $inpos - $offset;
+			switch ( $list[$inpos] ) {
+				case '\'':
+					$list[$outpos - 1] .= '\'';
+					$offset++;
+					break;
+				case '\\int':
+					$int++;
+					$offset++;
+					break;
+				case '\\mathrm{d}':
+				case 'd':
+					if ( $int ) {
+						$int--;
+						$offset++;
+						break;
+					}
+				// no break
+				default:
+					if ( isset( $list[0] ) ) {
+						$list[$outpos] = $list[$inpos];
+					}
+			}
+		}
+		return array_slice( $list, 0, count( $list ) - $offset );
+	}
+
+	public function getModIdent() {
+		$y = [];
+
+		foreach ( $this->args as $x ) {
+			$y = array_merge( $y, $x->getModIdent() );
+		}
+
+		if ( isset( $this->args[0] ) && ( count( $this->args ) == count( $y ) ) ) {
+			return implode( "", $y );
+		}
+		return [];
+	}
+
+	public function push( ...$elements ) {
+		self::checkInput( $elements );
+
+		array_push( $this->args, ...$elements );
+	}
+
+	/**
+	 * @throws InvalidArgumentException if first value not defined
+	 * @return TexNode|string first value
+	 */
+	public function first() {
+		if ( isset( $this->args[0] ) ) {
+			return $this->args[0];
+		} else {
+			throw new InvalidArgumentException( 'Input arguments not have been filled.' );
+		}
+	}
+
+	/**
+	 * @throws InvalidArgumentException if second value not defined
+	 * @return TexNode|string second value
+	 */
+	public function second() {
+		if ( isset( $this->args[1] ) ) {
+			return $this->args[1];
+		} else {
+			throw new InvalidArgumentException( 'Input arguments not have been filled.' );
+		}
+	}
+
+	public function name() {
+		return 'ARRAY';
+	}
+
+	/**
+	 * @throws InvalidArgumentException if args not of correct type
+	 * @param TexNode[] $args input args
+	 * @return void
+	 */
+	private static function checkInput( $args ): void {
+		foreach ( $args as $arg ) {
+			if ( !( $arg instanceof TexNode ) ) {
+				throw new InvalidArgumentException( 'Wrong input type specified in input elements.' );
+			}
+		}
+	}
+}
diff --git a/src/TexVC/Nodes/TexNode.php b/src/TexVC/Nodes/TexNode.php
index ab2322951..6cde08837 100644
--- a/src/TexVC/Nodes/TexNode.php
+++ b/src/TexVC/Nodes/TexNode.php
@@ -9,7 +9,7 @@ use InvalidArgumentException;
 class TexNode {
 
 	/** @var list<TexNode|string> */
-	private $args;
+	protected $args;
 
 	/**
 	 * Creates a TexNode
@@ -38,6 +38,14 @@ class TexNode {
 		return $child;
 	}
 
+	public function getLength(): ?int {
+		if ( isset( $this->args[0] ) ) {
+			return count( $this->args );
+		} else {
+			return 0;
+		}
+	}
+
 	/**
 	 * Wraps the rendered result in curly brackets.
 	 * @return string rendered result in curlies.
diff --git a/src/TexVC/Nodes/UQ.php b/src/TexVC/Nodes/UQ.php
new file mode 100644
index 000000000..c7bf78e85
--- /dev/null
+++ b/src/TexVC/Nodes/UQ.php
@@ -0,0 +1,27 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace MediaWiki\Extension\Math\TexVC\Nodes;
+
+class UQ extends TexNode {
+
+	/** @var TexNode */
+	private $base;
+	/** @var TexNode */
+	private $up;
+
+	public function __construct( TexNode $base, TexNode $down ) {
+		parent::__construct( $base, $down );
+		$this->base = $base;
+		$this->up = $down;
+	}
+
+	public function render() {
+		return $this->base->render() . '^' . $this->up->inCurlies();
+	}
+
+	public function name() {
+		return 'UQ';
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/BigTest.php b/tests/phpunit/unit/TexVC/Nodes/BigTest.php
new file mode 100644
index 000000000..e0fbb00eb
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/BigTest.php
@@ -0,0 +1,49 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\Big;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWikiUnitTestCase;
+use RuntimeException;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\Big
+ */
+class BigTest extends MediaWikiUnitTestCase {
+
+	public function testEmptyBig() {
+		$this->expectException( ArgumentCountError::class );
+		new Big();
+		throw new ArgumentCountError( 'Should not create an empty big' );
+	}
+
+	public function testOneArgumentBig() {
+		$this->expectException( ArgumentCountError::class );
+		new Big( '\\big' );
+		throw new ArgumentCountError( 'Should not create a big with one argument' );
+	}
+
+	public function testIncorrectTypeBig() {
+		$this->expectException( TypeError::class );
+		new Big( '\\big', new Literal( 'a' ) );
+		throw new RuntimeException( 'Should not create a big with incorrect type' );
+	}
+
+	public function testBasicFunctionBig() {
+		$big = new Big( '\\big', 'a' );
+		$this->assertEquals( '{\\big a}', $big->render(), 'Should create a basic function' );
+	}
+
+	public function testExtractIdentifiersBig() {
+		$big = new Big( '\\big', 'a' );
+		$this->assertEquals( [], $big->extractIdentifiers(), 'Should extract identifiers' );
+	}
+
+	public function testCurliesBig() {
+		$big = new Big( '\\big', 'a' );
+		$this->assertEquals( '{\\big a}', $big->inCurlies(), 'Should create exactly one set of curlies' );
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/BoxTest.php b/tests/phpunit/unit/TexVC/Nodes/BoxTest.php
new file mode 100644
index 000000000..2866b6f60
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/BoxTest.php
@@ -0,0 +1,49 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\Box;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWikiUnitTestCase;
+use RuntimeException;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\Box
+ */
+class BoxTest extends MediaWikiUnitTestCase {
+
+	public function testEmptyBox() {
+		$this->expectException( ArgumentCountError::class );
+		new Box();
+		throw new ArgumentCountError( 'Should not create an empty box' );
+	}
+
+	public function testOneArgumentBox() {
+		$this->expectException( ArgumentCountError::class );
+		new Box( '\\hbox' );
+		throw new ArgumentCountError( 'Should not create a box with one argument' );
+	}
+
+	public function testIncorrectTypeBox() {
+		$this->expectException( TypeError::class );
+		new Box( '\\hbox', new Literal( 'a' ) );
+		throw new RuntimeException( 'Should not create a box with incorrect type' );
+	}
+
+	public function testBasicFunctionBox() {
+		$box = new Box( '\\hbox', 'a' );
+		$this->assertEquals( '{\\hbox{a}}', $box->render(), 'Should create a basic function' );
+	}
+
+	public function testExtractIdentifiersBox() {
+		$box = new Box( '\\hbox', 'a' );
+		$this->assertEquals( [], $box->extractIdentifiers(), 'Should extract identifiers' );
+	}
+
+	public function testCurliesBox() {
+		$box = new Box( '\\hbox', 'a' );
+		$this->assertEquals( '{\\hbox{a}}', $box->inCurlies(), 'Should create exactly one set of curlies' );
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/ChemFun2uTest.php b/tests/phpunit/unit/TexVC/Nodes/ChemFun2uTest.php
new file mode 100644
index 000000000..d2a2828bd
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/ChemFun2uTest.php
@@ -0,0 +1,43 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\ChemFun2u;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWikiUnitTestCase;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\ChemFun2u
+ */
+class ChemFun2uTest extends MediaWikiUnitTestCase {
+
+	public function testEmptyChemFun2u() {
+		$this->expectException( ArgumentCountError::class );
+		new ChemFun2u();
+		throw new ArgumentCountError( 'Should not create an empty ChemFun2u' );
+	}
+
+	public function testOneArgumentChemFun2u() {
+		$this->expectException( ArgumentCountError::class );
+		new ChemFun2u( 'a' );
+		throw new ArgumentCountError( 'Should not create a ChemFun2u with one argument' );
+	}
+
+	public function testIncorrectTypeChemFun2u() {
+		$this->expectException( TypeError::class );
+		new ChemFun2u( 'a', 'b', 'c' );
+		throw new TypeError( 'Should not create a ChemFun2u with incorrect type' );
+	}
+
+	public function testBasicChemFun2u() {
+		$fun2u = new ChemFun2u( 'a', new Literal( 'b' ), new Literal( 'c' ) );
+		$this->assertEquals( 'a{b}_{c}', $fun2u->render(), 'Should create a basic ChemFun2u' );
+	}
+
+	public function testExtractIdentifiers() {
+		$fun2u = new ChemFun2u( 'a', new Literal( 'b' ), new Literal( 'c' ) );
+		$this->assertEquals( [], $fun2u->extractIdentifiers(), 'Should extract identifiers' );
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/ChemWordTest.php b/tests/phpunit/unit/TexVC/Nodes/ChemWordTest.php
new file mode 100644
index 000000000..4fcfad034
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/ChemWordTest.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\ChemWord;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWikiUnitTestCase;
+use RuntimeException;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\ChemWord
+ */
+class ChemWordTest extends MediaWikiUnitTestCase {
+
+	public function testEmptyChemWord() {
+		$this->expectException( ArgumentCountError::class );
+		new ChemWord();
+		throw new ArgumentCountError( 'Should not create an empty ChemWord' );
+	}
+
+	public function testOneArgumentChemWord() {
+		$this->expectException( ArgumentCountError::class );
+		new ChemWord( new Literal( 'a' ) );
+		throw new ArgumentCountError( 'Should not create a ChemWord with one argument' );
+	}
+
+	public function testIncorrectTypeChemWord() {
+		$this->expectException( TypeError::class );
+		new ChemWord( 'a', 'b' );
+		throw new RuntimeException( 'Should not create a ChemWord with incorrect type' );
+	}
+
+	public function testBasicFunctionChemWord() {
+		$chemWord = new ChemWord( new Literal( 'a' ), new Literal( 'b' ) );
+		$this->assertEquals( 'ab', $chemWord->render(), 'Should create a basic function' );
+	}
+
+	public function testExtractIdentifiersBox() {
+		$chemWord = new ChemWord( new Literal( 'a' ), new Literal( 'b' ) );
+		$this->assertEquals( [], $chemWord->extractIdentifiers(), 'Should extract identifiers' );
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/CurlyTest.php b/tests/phpunit/unit/TexVC/Nodes/CurlyTest.php
new file mode 100644
index 000000000..d8b7e37d4
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/CurlyTest.php
@@ -0,0 +1,72 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\Curly;
+use MediaWiki\Extension\Math\TexVC\Nodes\DQ;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWiki\Extension\Math\TexVC\Nodes\TexArray;
+use MediaWiki\Extension\Math\TexVC\Nodes\TexNode;
+use MediaWikiUnitTestCase;
+use RuntimeException;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\Curly
+ */
+class CurlyTest extends MediaWikiUnitTestCase {
+
+	public function testEmptyDollar() {
+		$this->expectException( ArgumentCountError::class );
+		new Curly();
+		throw new ArgumentCountError( 'Should not create an empty curly' );
+	}
+
+	public function testOneArgumentCurly() {
+		$this->expectException( ArgumentCountError::class );
+		new Curly( new TexArray( new TexNode( 'a' ) ), new TexArray( new TexNode( 'b' ) ) );
+		throw new ArgumentCountError( 'Should not create a curly with more than one argument' );
+	}
+
+	public function testIncorrectTypeCurly() {
+		$this->expectException( TypeError::class );
+		new Curly( new TexNode() );
+		throw new RuntimeException( 'Should not create a curly with incorrect type' );
+	}
+
+	public function testRenderTexCurly() {
+		$curly = new Curly( new TexArray() );
+		$this->assertEquals( '{}', $curly->render(), 'Should render a curly with empty tex array' );
+	}
+
+	public function testRenderListCurly() {
+		$curly = new Curly( new TexArray(
+		new Literal( 'hello' ),
+		new Literal( ' ' ),
+		new Literal( 'world' )
+		) );
+		$this->assertEquals( '{hello world}', $curly->render(), 'Should render a list' );
+	}
+
+	public function testNoExtraCurliesDQ() {
+		$dq = new DQ( new Literal( 'a' ),
+			new Curly( new TexArray( new Literal( 'b' ) ) ) );
+		$this->assertEquals( 'a_{b}', $dq->render(), 'Should not create extra curlies from dq' );
+	}
+
+	public function testNoExtraCurliesCurly() {
+		$curly = new Curly( new TexArray( new Literal( 'a' ) ) );
+		$this->assertEquals( '{a}', $curly->inCurlies(), 'Should not create extra curlies from curly' );
+	}
+
+	public function testExtractIdentifierModsCurly() {
+		$curly = new Curly( new TexArray( new Literal( 'b' ) ) );
+		$this->assertEquals( 'b', $curly->getModIdent(), 'Should extract identifier modifications' );
+	}
+
+	public function testExtractSubscirpts() {
+		$curly = new Curly( new TexArray( new Literal( 'b' ) ) );
+		$this->assertEquals( 'b', $curly->extractSubscripts(), 'Should extract subscripts' );
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/DeclhTest.php b/tests/phpunit/unit/TexVC/Nodes/DeclhTest.php
new file mode 100644
index 000000000..d9882802c
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/DeclhTest.php
@@ -0,0 +1,78 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\Declh;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWiki\Extension\Math\TexVC\Nodes\TexArray;
+
+use MediaWikiUnitTestCase;
+use RuntimeException;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\Declh
+ */
+class DeclhTest extends MediaWikiUnitTestCase {
+
+	public function testEmptyDeclh() {
+		$this->expectException( ArgumentCountError::class );
+		new Declh();
+		throw new ArgumentCountError( 'Should not create an empty Declh' );
+	}
+
+	public function testOneArgumentDeclh() {
+		$this->expectException( ArgumentCountError::class );
+		new Declh( '\\f' );
+		throw new ArgumentCountError( 'Should not create a Declh with one argument' );
+	}
+
+	public function testIncorrectTypeDeclh() {
+		$this->expectException( TypeError::class );
+		new Declh( '\\f', 'x' );
+		throw new RuntimeException( 'Should not create a Declh with incorrect type' );
+	}
+
+	public function testBasicFunctionDeclh() {
+		$f = new Declh( '\\rm', new TexArray( new Literal( 'a' ) ) );
+		$this->assertEquals( '{\\rm {a}}', $f->render(), 'Should create a basic function' );
+	}
+
+	public function testTwoArgsFunctionDeclh() {
+		$f = new Declh( '\\rm',
+			new TexArray( new Literal( 'a' ), new Literal( 'b' ) ) );
+		$this->assertEquals( '{\\rm {ab}}',
+			$f->render(), 'Should create a function with two arguments' );
+	}
+
+	public function testCurliesDeclh() {
+		$f = new Declh( '\\f', new TexArray( new Literal( 'a' ) ) );
+		$this->assertEquals( '{\\f {a}}', $f->inCurlies(), 'Should create exactly one set of curlies' );
+	}
+
+	public function testExtractIdentifiersDeclh() {
+		$f = new Declh( '\\rm', new TexArray( new Literal( 'a' ) ) );
+		$this->assertEquals( [ 'a' ], $f->extractIdentifiers(), 'Should extract identifiers' );
+	}
+
+	public function testExtractIdentifiersMultiDeclh() {
+		$f = new Declh( '\\rm', new TexArray( new Literal( 'a' ), new Literal( 'b' ) ) );
+		$this->assertEquals( [ 'ab' ], $f->extractIdentifiers(), 'Should extract multiple identifiers' );
+	}
+
+	public function testNotExtractSomeSubscripts() {
+		$f = new Declh( '\\bf', new TexArray( new Literal( '' ) ) );
+		$this->assertEquals( [], $f->extractSubscripts(),
+			'Should not extract empty font modifier subscripts identifiers' );
+	}
+
+	public function testSubscriptsForFontMod() {
+		$mods = [ 'rm','it','cal','bf' ];
+		foreach ( $mods as $mod ) {
+			$f = new Declh( "\\${mod}", new TexArray( new Literal( 'a' ) ) );
+			$this->assertEquals( [ "\\math${mod}{a}" ], $f->extractSubscripts(),
+				"Should extract subscripts for ${mod} font modification" );
+		}
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/DollarTest.php b/tests/phpunit/unit/TexVC/Nodes/DollarTest.php
new file mode 100644
index 000000000..b321c8490
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/DollarTest.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\Dollar;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWiki\Extension\Math\TexVC\Nodes\TexArray;
+use MediaWiki\Extension\Math\TexVC\Nodes\TexNode;
+use MediaWikiUnitTestCase;
+use RuntimeException;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\Dollar
+ */
+class DollarTest extends MediaWikiUnitTestCase {
+
+	public function testEmptyDollar() {
+		$this->expectException( ArgumentCountError::class );
+		new Dollar();
+		throw new ArgumentCountError( 'Should not create an empty dollar' );
+	}
+
+	public function testOneArgumentDollar() {
+		$this->expectException( ArgumentCountError::class );
+		new Dollar( new TexArray(), new TexArray() );
+		throw new ArgumentCountError( 'Should not create a dollar with more than one argument' );
+	}
+
+	public function testIncorrectTypeDollar() {
+		$this->expectException( TypeError::class );
+		new Dollar( new TexNode() );
+		throw new RuntimeException( 'Should not create a dollar with incorrect type' );
+	}
+
+	public function testRenderTexDollar() {
+		$dollar = new Dollar( new TexArray() );
+		$this->assertEquals( '$$', $dollar->render(), 'Should render a dollar with empty tex array' );
+	}
+
+	public function testRenderListDollar() {
+		$dollar = new Dollar( new TexArray(
+		new Literal( 'hello' ),
+		new Literal( ' ' ),
+		new Literal( 'world' )
+		) );
+		$this->assertEquals( '$hello world$', $dollar->render(), 'Should render a list' );
+	}
+
+	public function testExtractIdentifiersDollar() {
+		$dollar = new Dollar( new TexArray(
+		new Literal( 'a' ),
+		new Literal( 'b' ),
+		new Literal( 'c' )
+		) );
+		$this->assertEquals( [], $dollar->extractIdentifiers(), 'Should extract identifiers' );
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/Fun1Test.php b/tests/phpunit/unit/TexVC/Nodes/Fun1Test.php
new file mode 100644
index 000000000..0aee85668
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/Fun1Test.php
@@ -0,0 +1,95 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\Fun1;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWikiUnitTestCase;
+use RuntimeException;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\Fun1
+ */
+class Fun1Test extends MediaWikiUnitTestCase {
+
+	public function testEmptyFun1() {
+		$this->expectException( ArgumentCountError::class );
+		new Fun1();
+		throw new ArgumentCountError( 'Should not create an empty fun1' );
+	}
+
+	public function testOneArgumentFun1() {
+		$this->expectException( ArgumentCountError::class );
+		new Fun1( '\\f' );
+		throw new ArgumentCountError( 'Should not create a fun1 with one argument' );
+	}
+
+	public function testIncorrectTypeFun1() {
+		$this->expectException( TypeError::class );
+		new Fun1( '\\f', 'x' );
+		throw new RuntimeException( 'Should not create a fun1 with incorrect type' );
+	}
+
+	public function testBasicFunctionFun1() {
+		$f = new Fun1( '\\f', new Literal( 'a' ) );
+		$this->assertEquals( '{\\f {a}}', $f->render(),
+			'Should create a basic function' );
+	}
+
+	public function testCurliesFun1() {
+		$f = new Fun1( '\\f', new Literal( 'a' ) );
+		$this->assertEquals( '{\\f {a}}', $f->inCurlies(),
+			'Should create exactly one set of curlies' );
+	}
+
+	public function testExtractIdentifiersFun1() {
+		$f = new Fun1( '\\mathbf', new Literal( 'B' ) );
+		$this->assertEquals( [ '\\mathbf{B}' ], $f->extractIdentifiers(),
+			'Should extract identifiers' );
+	}
+
+	public function testExtractExtendedLiteralsFun1() {
+		$f = new Fun1( '\\mathbf', new Literal( '\\infty' ) );
+		$this->assertEquals( [], $f->extractIdentifiers(),
+			'Should not extract extended literals as identifiers.' );
+	}
+
+	public function testExtractPhantomIdentifiers() {
+		$f = new Fun1( '\\hphantom', new Literal( 'A' ) );
+		$this->assertEquals( [], $f->extractIdentifiers(),
+			'Should not extract phantom identifiers.' );
+	}
+
+	public function testIgnoreUnknownFunctions() {
+		$f = new Fun1( '\\unknown', new Literal( 'A' ) );
+		$this->assertEquals( [ 'A' ], $f->extractIdentifiers(),
+			'Should ignore unknown functions.' );
+	}
+
+	public function testExtractIdentifierMods() {
+		$f = new Fun1( '\\mathbf', new Literal( 'B' ) );
+		$this->assertEquals( [ '\\mathbf{B}' ], $f->getModIdent(),
+			'Should extract identifier modifications.' );
+	}
+
+	public function testExtractSubscripts() {
+		$f = new Fun1( '\\mathbf', new Literal( 'B' ) );
+		$this->assertEquals( [ '\\mathbf{B}' ],
+			$f->extractSubscripts(), 'Should extract subscripts.' );
+	}
+
+	public function testExtractSubscriptsExtendedLits() {
+		$f = new Fun1( '\\mathbf', new Literal( '\\infty' ) );
+		$this->assertEquals( [ '\\mathbf{\\infty}' ], $f->extractSubscripts(),
+			'Should extract subscripts for extended literals.' );
+	}
+
+	public function testExtractSubscriptsEmptyMods() {
+		$f = new Fun1( '\\mathbf', new Literal( '' ) );
+		$this->assertEquals( [], $f->extractSubscripts(),
+			'Should not extract subscripts for empty mods.' );
+	}
+
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/Fun1nbTest.php b/tests/phpunit/unit/TexVC/Nodes/Fun1nbTest.php
new file mode 100644
index 000000000..501301b04
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/Fun1nbTest.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\Fun1nb;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWikiUnitTestCase;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\Fun1nb
+ */
+class Fun1nbTest extends MediaWikiUnitTestCase {
+
+	public function testEmptyFun1nb() {
+		$this->expectException( ArgumentCountError::class );
+		new Fun1nb();
+		throw new ArgumentCountError( 'Should not create an empty fun1nb' );
+	}
+
+	public function testOneArgumentFun1nb() {
+		$this->expectException( ArgumentCountError::class );
+		new Fun1nb( '\\f' );
+		throw new ArgumentCountError( 'Should not create a fun1nb with one argument' );
+	}
+
+	public function testIncorrectTypeFun1nb() {
+		$this->expectException( TypeError::class );
+		new Fun1nb( '\\f', 'x' );
+		throw new TypeError( 'Should not create a fun1nb with incorrect type' );
+	}
+
+	public function testBasicFunctionFun1nb() {
+		$fq = new Fun1nb( '\\f', new Literal( 'a' ) );
+		$this->assertEquals( '\\f {a} ', $fq->render(), 'Should create a basic function' );
+	}
+
+	public function testCurliesFun1nb() {
+		$f = new Fun1nb( '\\f', new Literal( 'a' ) );
+		$this->assertEquals( '{\\f {a} }', $f->inCurlies(),
+			'Should create exactly one set of curlies' );
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/Fun2Test.php b/tests/phpunit/unit/TexVC/Nodes/Fun2Test.php
new file mode 100644
index 000000000..2af753fff
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/Fun2Test.php
@@ -0,0 +1,52 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\Fun2;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWikiUnitTestCase;
+use RuntimeException;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\Fun2
+ */
+class Fun2Test extends MediaWikiUnitTestCase {
+
+	public function testEmptyFun2() {
+		$this->expectException( ArgumentCountError::class );
+		new Fun2();
+		throw new ArgumentCountError( 'Should not create an empty fun2' );
+	}
+
+	public function testOneArgumentFun2() {
+		$this->expectException( ArgumentCountError::class );
+		new Fun2( '\\f' );
+		throw new ArgumentCountError( 'Should not create a fun2 with one argument' );
+	}
+
+	public function testIncorrectTypeFun2() {
+		$this->expectException( TypeError::class );
+		new Fun2( '\\f', 'x', 'y' );
+		throw new RuntimeException( 'Should not create a fun2 with incorrect types' );
+	}
+
+	public function testBasicFunctionFun2() {
+		$f = new Fun2( '\\f', new Literal( 'a' ), new Literal( 'b' ) );
+		$this->assertEquals( '{\\f {a}{b}}', $f->render(),
+			'Should create a basic function' );
+	}
+
+	public function testCurliesFun2() {
+		$f = new Fun2( '\\f', new Literal( 'a' ), new Literal( 'b' ) );
+		$this->assertEquals( '{\\f {a}{b}}', $f->inCurlies(),
+			'Should create exactly one set of curlies' );
+	}
+
+	public function testExtractIdentifiersFun2() {
+		$f = new Fun2( '\\f', new Literal( 'a' ), new Literal( 'b' ) );
+		$this->assertEquals( [ 'a','b' ], $f->extractIdentifiers(),
+			'Should extract identifiers' );
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/Fun2nbTest.php b/tests/phpunit/unit/TexVC/Nodes/Fun2nbTest.php
new file mode 100644
index 000000000..03c47e736
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/Fun2nbTest.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\Fun2nb;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWikiUnitTestCase;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\Fun2nb
+ */
+class Fun2nbTest extends MediaWikiUnitTestCase {
+
+	public function testEmptyFun2nb() {
+		$this->expectException( ArgumentCountError::class );
+		new Fun2nb();
+		throw new ArgumentCountError( 'Should not create an empty fun2nb' );
+	}
+
+	public function testOneArgumentFun2nb() {
+		$this->expectException( ArgumentCountError::class );
+		new Fun2nb( '\\f' );
+		throw new ArgumentCountError( 'Should not create a fun2nb with one argument' );
+	}
+
+	public function testIncorrectTypeFun2nb() {
+		$this->expectException( TypeError::class );
+		new Fun2nb( '\\f', 'x', 'y' );
+		throw new TypeError( 'Should not create a fun2nb with incorrect type' );
+	}
+
+	public function testBasicFunctionFun2nb() {
+		$fq = new Fun2nb( '\\f', new Literal( 'a' ), new Literal( 'b' ) );
+		$this->assertEquals( '\\f {a}{b}', $fq->render(), 'Should create a basic function' );
+	}
+
+	public function testCurliesFun2nb() {
+		$f = new Fun2nb( '\\f', new Literal( 'a' ), new Literal( 'b' ) );
+		$this->assertEquals( '{\\f {a}{b}}', $f->inCurlies(),
+			'Should create exactly one set of curlies' );
+	}
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/TexArrayTest.php b/tests/phpunit/unit/TexVC/Nodes/TexArrayTest.php
new file mode 100644
index 000000000..3c65a8661
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/TexArrayTest.php
@@ -0,0 +1,77 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWiki\Extension\Math\TexVC\Nodes\TexArray;
+use MediaWiki\Extension\Math\TexVC\Nodes\TexNode;
+use MediaWikiUnitTestCase;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\TexArray
+ */
+class TexArrayTest extends MediaWikiUnitTestCase {
+
+	public function testIsTexNode() {
+		$this->assertEquals( new TexArray() instanceof TexNode, true,
+			'Should create an instance of TexNode' );
+	}
+
+	public function testConcatOutput() {
+		$ta = new TexArray( new Literal( 'a' ), new Literal( 'b' ) );
+		$this->assertEquals( 'ab', $ta->render(), 'Should concatenate its input' );
+	}
+
+	public function testExtractCurlies() {
+		$n = new TexNode( new TexArray( new Literal( 'a' ) ) );
+		$this->assertEquals( '{a}', $n->inCurlies(),
+			'Should create exactly one pair of curlies' );
+	}
+
+	public function testExtractIdentifiers() {
+		$n = new TexArray( new Literal( 'd' ) );
+		$this->assertEquals( [ 'd' ], $n->extractIdentifiers(),
+			'Should extract identifiers' );
+	}
+
+	public function testExtractIdentifiersFromArg() {
+		$n = new TexArray();
+		$this->assertEquals( [ 'd' ],
+			$n->extractIdentifiers( [ new Literal( 'd' ) ] ),
+			'Should extract identifiers from the argument' );
+	}
+
+	public function testExtractSplitIdentifiers() {
+		$n = new TexArray( new Literal( 'a' ), new Literal( '\'' ) );
+		$this->assertEquals( [ 'a\'' ], $n->extractIdentifiers(),
+			'Should extract split identifiers' );
+	}
+
+	public function testNotConfuseIntegralsIdentifiers() {
+		$n = new TexArray( new Literal( 'd' ), new Literal( '\\int' ) );
+		$this->assertEquals( [ 'd' ], $n->extractIdentifiers(),
+			'Should not confuse integrals and identifiers' );
+	}
+
+	public function testNotConfuseIntegralD() {
+		$n = new TexArray( new Literal( '\\int' ), new Literal( 'd' ) );
+		$this->assertEquals( [], $n->extractIdentifiers(), 'Should not confuse integral d with d identifier' );
+	}
+
+	public function testNotConfuseUprightIntegralD() {
+		$n = new TexArray( new Literal( '\\int' ), new Literal( '\\mathrm{d}' ) );
+		$this->assertEquals( [], $n->extractIdentifiers(),
+			'Should not confuse upright integral d with d identifier' );
+	}
+
+	public function testExtractIdentifierMods() {
+		$n = new TexArray( new TexNode( '' ) );
+		$this->assertEquals( [], $n->getModIdent(), 'Should extract identifier modifications' );
+	}
+
+	public function testExtractSubscripts() {
+		$n = new TexArray( new TexNode( '' ) );
+		$this->assertEquals( [], $n->extractSubscripts(), 'Should extract subscripts' );
+	}
+
+}
diff --git a/tests/phpunit/unit/TexVC/Nodes/UQTest.php b/tests/phpunit/unit/TexVC/Nodes/UQTest.php
new file mode 100644
index 000000000..6fe739d53
--- /dev/null
+++ b/tests/phpunit/unit/TexVC/Nodes/UQTest.php
@@ -0,0 +1,45 @@
+<?php
+
+namespace MediaWiki\Extension\Math\Tests\TexVC\Nodes;
+
+use ArgumentCountError;
+use MediaWiki\Extension\Math\TexVC\Nodes\Literal;
+use MediaWiki\Extension\Math\TexVC\Nodes\TexNode;
+use MediaWiki\Extension\Math\TexVC\Nodes\UQ;
+use MediaWikiUnitTestCase;
+use RuntimeException;
+use TypeError;
+
+/**
+ * @covers \MediaWiki\Extension\Math\TexVC\Nodes\UQ
+ */
+class UQTest extends MediaWikiUnitTestCase {
+
+	public function testEmptyUQ() {
+		$this->expectException( ArgumentCountError::class );
+		new UQ();
+		throw new ArgumentCountError( 'Should not create an empty uq' );
+	}
+
+	public function testOneArgumentUQ() {
+		$this->expectException( ArgumentCountError::class );
+		new UQ( new Literal( 'a' ) );
+		throw new ArgumentCountError( 'Should not create a uq with one argument' );
+	}
+
+	public function testIncorrectTypeUQ() {
+		$this->expectException( TypeError::class );
+		new UQ( 'a', 'b' );
+		throw new RuntimeException( 'Should not create a uq with incorrect type' );
+	}
+
+	public function testBasicUQ() {
+		$uq = new UQ( new Literal( 'a' ), new Literal( 'b' ) );
+		$this->assertEquals( 'a^{b}', $uq->render(), 'Should create a basic uq' );
+	}
+
+	public function testEmptyBaseUQ() {
+		$uq = new UQ( new TexNode(), new Literal( 'b' ) );
+		$this->assertEquals( '^{b}', $uq->render(), 'Should create an empty base uq' );
+	}
+}