Assert: Introduce strict boolean true/false assertions

Fixes #1444.
Closes #1445.

docs/assert/false.md

@@ -0,0 +1,38 @@
+---
+layout: default
+title: false
+description: A strict boolean false comparison.
+categories:
+  - assert
+---
+
+## `false( actual [, message ] )`
+
+A boolean check, equivalent to JUnit's `assertFalse()`. Passes if the first argument is false.
+
+| name               | description                          |
+|--------------------|--------------------------------------|
+| `actual`           | Expression being tested              |
+| `message` (string) | A short description of the assertion |
+
+### Description
+
+`false()` requires just one argument. If the argument evaluates to false, the assertion passes; otherwise, it fails.
+
+[`true()`](/assert/true) can be used to explicitly test for a true value.
+
+### Examples
+
+```js
+QUnit.test( "false test", function( assert ) {
+  assert.false( false, "false succeeds" );
+
+  assert.false( "not-empty", "not-empty string fails" );
+  assert.false( "", "empty string fails" );
+  assert.false( 0, "0 fails" );
+  assert.false( true, "true fails" );
+  assert.false( NaN, "NaN fails" );
+  assert.false( null, "null fails" );
+  assert.false( undefined, "undefined fails" );
+});
+```

docs/assert/true.md

@@ -0,0 +1,39 @@
+---
+layout: default
+title: true
+description: A strict boolean true comparison.
+categories:
+  - assert
+---
+
+## `true( actual [, message ] )`
+
+A boolean check, equivalent to JUnit's `assertTrue()`. Passes if the first argument is `true`.
+
+| name               | description                          |
+|--------------------|--------------------------------------|
+| `actual`           | Expression being tested              |
+| `message` (string) | A short description of the assertion |
+
+### Description
+
+`true()` requires just one argument. If the argument evaluates to true, the assertion passes; otherwise, it fails.
+
+[`false()`](/assert/false) can be used to explicitly test for a false value.
+
+### Examples
+
+```js
+QUnit.test( "true test", function( assert ) {
+  assert.true( true, "true succeeds" );
+
+  assert.true( "non-empty", "non-empty string fails" );
+  assert.true( "", "empty string fails" );
+  assert.true( 1, "1 fails" );
+  assert.true( false, "false fails" );
+  assert.true( NaN, "NaN fails" );
+  assert.true( null, "null fails" );
+  assert.true( undefined, "undefined fails" );
+});
+```
+

src/assert.js

@@ -173,6 +173,24 @@ class Assert {
 		} );
 	}
 
+	true( result, message ) {
+		this.pushResult( {
+			result: result === true,
+			actual: result,
+			expected: true,
+			message
+		} );
+	}
+
+	false( result, message ) {
+		this.pushResult( {
+			result: result === false,
+			actual: result,
+			expected: false,
+			message
+		} );
+	}
+
 	equal( actual, expected, message ) {
 
 		// eslint-disable-next-line eqeqeq

test/main/assert.js

@@ -38,6 +38,22 @@ QUnit.test( "notOk", function( assert ) {
 	assert.notOk( NaN );
 } );
 
+QUnit.test( "true", function( assert ) {
+	function functionThatReturnsTrue() {
+		return true;
+	}
+	assert.true( true );
+	assert.true( functionThatReturnsTrue() );
+} );
+
+QUnit.test( "false", function( assert ) {
+	function functionThatReturnsFalse() {
+		return false;
+	}
+	assert.false( false );
+	assert.false( functionThatReturnsFalse() );
+} );
+
 QUnit.test( "equal", function( assert ) {
 	assert.equal( 1, 1 );
 	assert.equal( "foo", "foo" );