diff --git a/src/common/all_test.ts b/src/common/all_test.ts
index bb9fdea..c9a2065 100644
--- a/src/common/all_test.ts
+++ b/src/common/all_test.ts
@@ -2,6 +2,7 @@ import Ansi, * as _Ansi from './ansi.ts';
 import Buffer from './buffer.ts';
 import Document from './document.ts';
 import Editor from './editor.ts';
+import { highlightToColor, HighlightType } from './highlight.ts';
 import Position from './position.ts';
 import Row from './row.ts';
 
@@ -10,7 +11,8 @@ import { defaultTerminalSize, SCROLL_TAB_SIZE } from './config.ts';
 import { getTestRunner } from './runtime.ts';
 
 const {
-	assertEquals,
+	assertStrictEquals: assertEquals,
+	assertEquals: assertLooseEquals,
 	assertExists,
 	assertInstanceOf,
 	assertNotEquals,
@@ -20,6 +22,203 @@ const {
 	testSuite,
 } = await getTestRunner();
 
+const THIS_FILE = './src/common/all_test.ts';
+
+// ----------------------------------------------------------------------------
+// Helper Function Tests
+// ----------------------------------------------------------------------------
+
+const fnTest = () => {
+	const {
+		some,
+		none,
+		arrayInsert,
+		noop,
+		posSub,
+		minSub,
+		maxAdd,
+		ord,
+		strChars,
+		ctrlKey,
+		isControl,
+		isAscii,
+		isAsciiDigit,
+		strlen,
+		truncate,
+	} = Fn;
+
+	return {
+		'some()': () => {
+			assertFalse(some(null));
+			assertFalse(some(void 0));
+			assertFalse(some(undefined));
+			assertTrue(some(0));
+			assertTrue(some(false));
+		},
+		'none()': () => {
+			assertTrue(none(null));
+			assertTrue(none(void 0));
+			assertTrue(none(undefined));
+			assertFalse(none(0));
+			assertFalse(none(false));
+		},
+		'arrayInsert() strings': () => {
+			const a = ['😺', '😸', '😹'];
+			const b = arrayInsert(a, 1, 'x');
+			const c = ['😺', 'x', '😸', '😹'];
+			assertLooseEquals(b, c);
+
+			const d = arrayInsert(c, 17, 'y');
+			const e = ['😺', 'x', '😸', '😹', 'y'];
+			assertLooseEquals(d, e);
+
+			assertLooseEquals(arrayInsert([], 0, 'foo'), ['foo']);
+		},
+		'arrayInsert() numbers': () => {
+			const a = [1, 3, 5];
+			const b = [1, 3, 4, 5];
+			assertLooseEquals(arrayInsert(a, 2, 4), b);
+
+			const c = [1, 2, 3, 4, 5];
+			assertLooseEquals(arrayInsert(b, 1, 2), c);
+		},
+		'noop fn': () => {
+			assertExists(noop);
+			assertEquals(noop(), undefined);
+		},
+		'posSub()': () => {
+			assertEquals(posSub(14, 15), 0);
+			assertEquals(posSub(15, 1), 14);
+		},
+		'minSub()': () => {
+			assertEquals(minSub(13, 25, -1), -1);
+			assertEquals(minSub(25, 13, 0), 12);
+		},
+		'maxAdd()': () => {
+			assertEquals(maxAdd(99, 99, 75), 75);
+			assertEquals(maxAdd(25, 74, 101), 99);
+		},
+		'ord()': () => {
+			// Invalid output
+			assertEquals(ord(''), 256);
+
+			// Valid output
+			assertEquals(ord('a'), 97);
+		},
+		'strChars() properly splits strings into unicode characters': () => {
+			assertLooseEquals(strChars('😺😸😹'), ['😺', '😸', '😹']);
+		},
+		'ctrlKey()': () => {
+			const ctrl_a = ctrlKey('a');
+			assertTrue(isControl(ctrl_a));
+			assertEquals(ctrl_a, String.fromCodePoint(0x01));
+
+			const invalid = ctrlKey('😺');
+			assertFalse(isControl(invalid));
+			assertEquals(invalid, '😺');
+		},
+		'isAscii()': () => {
+			assertTrue(isAscii('asjyverkjhsdf1928374'));
+			assertFalse(isAscii('😺acalskjsdf'));
+			assertFalse(isAscii('ab😺ac'));
+		},
+		'isAsciiDigit()': () => {
+			assertTrue(isAsciiDigit('1234567890'));
+			assertFalse(isAsciiDigit('A1'));
+			assertFalse(isAsciiDigit('/'));
+			assertFalse(isAsciiDigit(':'));
+		},
+		'isControl()': () => {
+			assertFalse(isControl('abc'));
+			assertTrue(isControl(String.fromCodePoint(0x01)));
+			assertFalse(isControl('😺'));
+		},
+		'strlen()': () => {
+			// Ascii length
+			assertEquals(strlen('abc'), 'abc'.length);
+
+			// Get number of visible unicode characters
+			assertEquals(strlen('😺😸😹'), 3);
+			assertNotEquals('😺😸😹'.length, strlen('😺😸😹'));
+
+			// Skin tone modifier + base character
+			assertEquals(strlen('🤰🏼'), 2);
+			assertNotEquals('🤰🏼'.length, strlen('🤰🏼'));
+
+			// This has 4 sub-characters, and 3 zero-width-joiners
+			assertEquals(strlen('👨‍👩‍👧‍👦'), 7);
+			assertNotEquals('👨‍👩‍👧‍👦'.length, strlen('👨‍👩‍👧‍👦'));
+		},
+		'truncate()': () => {
+			assertEquals(truncate('😺😸😹', 1), '😺');
+			assertEquals(truncate('😺😸😹', 5), '😺😸😹');
+			assertEquals(truncate('👨‍👩‍👧‍👦', 5), '👨‍👩‍👧');
+		},
+	};
+};
+
+const readKeyTest = () => {
+	const { KeyCommand } = _Ansi;
+	const { readKey, ctrlKey } = Fn;
+
+	const encoder = new TextEncoder();
+
+	const testKeyMap = (codes: string[], expected: string) => {
+		codes.forEach((code) => {
+			assertEquals(readKey(encoder.encode(code)), expected);
+		});
+	};
+
+	return {
+		'empty input': () => {
+			assertEquals(readKey(new Uint8Array(0)), '');
+		},
+		'passthrough': () => {
+			// Ignore unhandled escape sequences
+			assertEquals(readKey(encoder.encode('\x1b[]')), '\x1b[]');
+
+			// Pass explicitly mapped values right through
+			assertEquals(
+				readKey(encoder.encode(KeyCommand.ArrowUp)),
+				KeyCommand.ArrowUp,
+			);
+			assertEquals(
+				readKey(encoder.encode(KeyCommand.Home)),
+				KeyCommand.Home,
+			);
+			assertEquals(
+				readKey(encoder.encode(KeyCommand.Delete)),
+				KeyCommand.Delete,
+			);
+
+			// And pass through whatever else
+			assertEquals(readKey(encoder.encode('foobaz')), 'foobaz');
+		},
+
+		'Esc': () => testKeyMap(['\x1b', ctrlKey('l')], KeyCommand.Escape),
+		'Backspace': () =>
+			testKeyMap(
+				[ctrlKey('h'), '\x7f'],
+				KeyCommand.Backspace,
+			),
+		'Home': () =>
+			testKeyMap(['\x1b[1~', '\x1b[7~', '\x1b[H', '\x1bOH'], KeyCommand.Home),
+		'End': () =>
+			testKeyMap(['\x1b[4~', '\x1b[8~', '\x1b[F', '\x1bOF'], KeyCommand.End),
+		'Enter': () => testKeyMap(['\n', '\r', '\v'], KeyCommand.Enter),
+	};
+};
+
+const highlightToColorTest = {
+	'highlightToColor()': () => {
+		assertTrue(highlightToColor(HighlightType.Number).length > 0);
+		assertTrue(highlightToColor(HighlightType.Match).length > 0);
+		assertTrue(highlightToColor(HighlightType.None).length > 0);
+	},
+};
+
+// ----------------------------------------------------------------------------
+// Tests by module
 // ----------------------------------------------------------------------------
 
 const ANSITest = () => {
@@ -100,6 +299,25 @@ const DocumentTest = {
 		assertTrue(doc.isEmpty());
 		assertEquals(doc.row(0), null);
 	},
+	'.open': async () => {
+		const oldDoc = Document.default();
+		oldDoc.insert(Position.default(), 'foobarbaz');
+		assertTrue(oldDoc.dirty);
+		assertEquals(oldDoc.numRows, 1);
+
+		const doc = await oldDoc.open(THIS_FILE);
+		assertFalse(doc.dirty);
+		assertFalse(doc.isEmpty());
+		assertTrue(doc.numRows > 1);
+	},
+	'.save': async () => {
+		const doc = await Document.default().open(THIS_FILE);
+		doc.insertNewline(Position.default());
+		assertTrue(doc.dirty);
+
+		await doc.save('test.file');
+		assertFalse(doc.dirty);
+	},
 	'.insertRow': () => {
 		const doc = Document.default();
 		doc.insertRow(undefined, 'foobar');
@@ -130,11 +348,52 @@ const DocumentTest = {
 		assertEquals(doc.numRows, 2);
 		assertTrue(doc.dirty);
 	},
+	'.insertNewline': () => {
+		// Invalid insert location
+		const doc = Document.default();
+		doc.insertNewline(Position.at(0, 3));
+		assertFalse(doc.dirty);
+		assertTrue(doc.isEmpty());
+
+		// Add new empty row
+		const doc2 = Document.default();
+		doc2.insertNewline(Position.default());
+		assertTrue(doc2.dirty);
+		assertFalse(doc2.isEmpty());
+
+		// Split an existing line
+		const doc3 = Document.default();
+		doc3.insert(Position.default(), 'foobar');
+		doc3.insertNewline(Position.at(3, 0));
+		assertEquals(doc3.numRows, 2);
+		assertEquals(doc3.row(0)?.toString(), 'foo');
+		assertEquals(doc3.row(1)?.toString(), 'bar');
+	},
 	'.delete': () => {
 		const doc = Document.default();
 		doc.insert(Position.default(), 'foobar');
 		doc.delete(Position.at(3, 0));
 		assertEquals(doc.row(0)?.toString(), 'fooar');
+
+		// Merge previous row
+		const doc2 = Document.default();
+		doc2.insertNewline(Position.default());
+		doc2.insert(Position.at(0, 1), 'foobar');
+		doc2.delete(Position.at(0, 1));
+		assertEquals(doc2.row(0)?.toString(), 'foobar');
+
+		// Merge next row
+		const doc3 = Document.default();
+		doc3.insertNewline(Position.default());
+		doc3.insert(Position.at(0, 1), 'foobar');
+		doc3.delete(Position.at(0, 0));
+		assertEquals(doc3.row(0)?.toString(), 'foobar');
+
+		// Invalid delete location
+		const doc4 = Document.default();
+		doc4.insert(Position.default(), 'foobar');
+		doc4.delete(Position.at(0, 1));
+		assertEquals(doc4.row(0)?.toString(), 'foobar');
 	},
 };
 
@@ -145,6 +404,21 @@ const EditorTest = {
 		const e = new Editor(defaultTerminalSize);
 		assertInstanceOf(e, Editor);
 	},
+	'.open': async () => {
+		const e = new Editor(defaultTerminalSize);
+		await e.open(THIS_FILE);
+		assertInstanceOf(e, Editor);
+	},
+	'.processKeyPress - letters': async () => {
+		const e = new Editor(defaultTerminalSize);
+		const res = await e.processKeyPress('a');
+		assertTrue(res);
+	},
+	'.processKeyPress - ctrl-q': async () => {
+		const e = new Editor(defaultTerminalSize);
+		const res = await e.processKeyPress(Fn.ctrlKey('q'));
+		assertFalse(res);
+	},
 };
 
 // ----------------------------------------------------------------------------
@@ -262,200 +536,21 @@ const RowTest = {
 
 // ----------------------------------------------------------------------------
 
-const fnTest = () => {
-	const {
-		some,
-		none,
-		arrayInsert,
-		noop,
-		posSub,
-		minSub,
-		maxAdd,
-		ord,
-		strChars,
-		ctrlKey,
-		isControl,
-		isAscii,
-		isAsciiDigit,
-		strlen,
-		truncate,
-	} = Fn;
-
-	return {
-		'some()': () => {
-			assertFalse(some(null));
-			assertFalse(some(void 0));
-			assertFalse(some(undefined));
-			assertTrue(some(0));
-			assertTrue(some(false));
-		},
-		'none()': () => {
-			assertTrue(none(null));
-			assertTrue(none(void 0));
-			assertTrue(none(undefined));
-			assertFalse(none(0));
-			assertFalse(none(false));
-		},
-		'arrayInsert() strings': () => {
-			const a = ['😺', '😸', '😹'];
-			const b = arrayInsert(a, 1, 'x');
-			const c = ['😺', 'x', '😸', '😹'];
-			assertEquals(b, c);
-
-			const d = arrayInsert(c, 17, 'y');
-			const e = ['😺', 'x', '😸', '😹', 'y'];
-			assertEquals(d, e);
-
-			assertEquals(arrayInsert([], 0, 'foo'), ['foo']);
-		},
-		'arrayInsert() numbers': () => {
-			const a = [1, 3, 5];
-			const b = [1, 3, 4, 5];
-			assertEquals(arrayInsert(a, 2, 4), b);
-
-			const c = [1, 2, 3, 4, 5];
-			assertEquals(arrayInsert(b, 1, 2), c);
-		},
-		'noop fn': () => {
-			assertExists(noop);
-			assertEquals(noop(), undefined);
-		},
-		'posSub()': () => {
-			assertEquals(posSub(14, 15), 0);
-			assertEquals(posSub(15, 1), 14);
-		},
-		'minSub()': () => {
-			assertEquals(minSub(13, 25, -1), -1);
-			assertEquals(minSub(25, 13, 0), 12);
-		},
-		'maxAdd()': () => {
-			assertEquals(maxAdd(99, 99, 75), 75);
-			assertEquals(maxAdd(25, 74, 101), 99);
-		},
-		'ord()': () => {
-			// Invalid output
-			assertEquals(ord(''), 256);
-
-			// Valid output
-			assertEquals(ord('a'), 97);
-		},
-		'strChars() properly splits strings into unicode characters': () => {
-			assertEquals(strChars('😺😸😹'), ['😺', '😸', '😹']);
-		},
-		'ctrlKey()': () => {
-			const ctrl_a = ctrlKey('a');
-			assertTrue(isControl(ctrl_a));
-			assertEquals(ctrl_a, String.fromCodePoint(0x01));
-
-			const invalid = ctrlKey('😺');
-			assertFalse(isControl(invalid));
-			assertEquals(invalid, '😺');
-		},
-		'isAscii()': () => {
-			assertTrue(isAscii('asjyverkjhsdf1928374'));
-			assertFalse(isAscii('😺acalskjsdf'));
-			assertFalse(isAscii('ab😺ac'));
-		},
-		'isAsciiDigit()': () => {
-			assertTrue(isAsciiDigit('1234567890'));
-			assertFalse(isAsciiDigit('A1'));
-			assertFalse(isAsciiDigit('/'));
-			assertFalse(isAsciiDigit(':'));
-		},
-		'isControl()': () => {
-			assertFalse(isControl('abc'));
-			assertTrue(isControl(String.fromCodePoint(0x01)));
-			assertFalse(isControl('😺'));
-		},
-		'strlen()': () => {
-			// Ascii length
-			assertEquals(strlen('abc'), 'abc'.length);
-
-			// Get number of visible unicode characters
-			assertEquals(strlen('😺😸😹'), 3);
-			assertNotEquals('😺😸😹'.length, strlen('😺😸😹'));
-
-			// Skin tone modifier + base character
-			assertEquals(strlen('🤰🏼'), 2);
-			assertNotEquals('🤰🏼'.length, strlen('🤰🏼'));
-
-			// This has 4 sub-characters, and 3 zero-width-joiners
-			assertEquals(strlen('👨‍👩‍👧‍👦'), 7);
-			assertNotEquals('👨‍👩‍👧‍👦'.length, strlen('👨‍👩‍👧‍👦'));
-		},
-		'truncate()': () => {
-			assertEquals(truncate('😺😸😹', 1), '😺');
-			assertEquals(truncate('😺😸😹', 5), '😺😸😹');
-			assertEquals(truncate('👨‍👩‍👧‍👦', 5), '👨‍👩‍👧');
-		},
-	};
-};
-
-// ----------------------------------------------------------------------------
-
-const readKeyTest = () => {
-	const { KeyCommand } = _Ansi;
-	const { readKey, ctrlKey } = Fn;
-
-	const encoder = new TextEncoder();
-
-	const testKeyMap = (codes: string[], expected: string) => {
-		codes.forEach((code) => {
-			assertEquals(readKey(encoder.encode(code)), expected);
-		});
-	};
-
-	return {
-		'empty input': () => {
-			assertEquals(readKey(new Uint8Array(0)), '');
-		},
-		'passthrough': () => {
-			// Ignore unhandled escape sequences
-			assertEquals(readKey(encoder.encode('\x1b[]')), '\x1b[]');
-
-			// Pass explicitly mapped values right through
-			assertEquals(
-				readKey(encoder.encode(KeyCommand.ArrowUp)),
-				KeyCommand.ArrowUp,
-			);
-			assertEquals(
-				readKey(encoder.encode(KeyCommand.Home)),
-				KeyCommand.Home,
-			);
-			assertEquals(
-				readKey(encoder.encode(KeyCommand.Delete)),
-				KeyCommand.Delete,
-			);
-
-			// And pass through whatever else
-			assertEquals(readKey(encoder.encode('foobaz')), 'foobaz');
-		},
-
-		'Esc': () => testKeyMap(['\x1b', ctrlKey('l')], KeyCommand.Escape),
-		'Backspace': () =>
-			testKeyMap(
-				[ctrlKey('h'), '\x7f'],
-				KeyCommand.Backspace,
-			),
-		'Home': () =>
-			testKeyMap(['\x1b[1~', '\x1b[7~', '\x1b[H', '\x1bOH'], KeyCommand.Home),
-		'End': () =>
-			testKeyMap(['\x1b[4~', '\x1b[8~', '\x1b[F', '\x1bOF'], KeyCommand.End),
-		'Enter': () => testKeyMap(['\n', '\r', '\v'], KeyCommand.Enter),
-	};
-};
+const SearchTest = {};
 
 // ----------------------------------------------------------------------------
 // Test Suite Setup
 // ----------------------------------------------------------------------------
 
 testSuite({
+	fns: fnTest(),
+	highlightToColorTest,
+	'readKey()': readKeyTest(),
 	'ANSI utils': ANSITest(),
 	Buffer: BufferTest,
 	Document: DocumentTest,
 	Editor: EditorTest,
 	Position: PositionTest,
 	Row: RowTest,
-	fns: fnTest(),
-	'readKey()': readKeyTest(),
+	Search: SearchTest,
 });
diff --git a/src/common/document.ts b/src/common/document.ts
index 69ed56d..9d58841 100644
--- a/src/common/document.ts
+++ b/src/common/document.ts
@@ -58,7 +58,7 @@ export class Document {
 	/**
 	 * Save the current document
 	 */
-	public async save(filename: string) {
+	public async save(filename: string): Promise<void> {
 		const { file } = await getRuntime();
 
 		await file.saveFile(filename, this.rowsToString());
@@ -66,7 +66,7 @@ export class Document {
 		this.dirty = false;
 	}
 
-	public resetFind() {
+	public resetFind(): void {
 		this.#search = new Search();
 		this.#search.parent = this;
 	}
@@ -108,16 +108,23 @@ export class Document {
 		this.dirty = true;
 	}
 
+	/**
+	 * Insert a new line, splitting and/or creating a new row as needed
+	 */
 	public insertNewline(at: Position): void {
 		if (at.y > this.numRows) {
 			return;
 		}
 
+		// Just add a simple blank line
 		if (at.y === this.numRows) {
 			this.#rows.push(Row.default());
+			this.dirty = true;
 			return;
 		}
 
+		// Split the current row, and insert a new
+		// row with the leftovers
 		const newRow = this.#rows[at.y].split(at.x);
 		newRow.update();
 		this.#rows = arrayInsert(this.#rows, at.y + 1, newRow);
diff --git a/src/common/editor.ts b/src/common/editor.ts
index 9058c46..5a5e8f4 100644
--- a/src/common/editor.ts
+++ b/src/common/editor.ts
@@ -337,6 +337,7 @@ class Editor {
 
 	/**
 	 * Filter out any additional unwanted keyboard input
+	 *
 	 * @param input
 	 * @private
 	 */
diff --git a/src/deno/test_base.ts b/src/deno/test_base.ts
index 0ebaeac..c7f1820 100644
--- a/src/deno/test_base.ts
+++ b/src/deno/test_base.ts
@@ -4,7 +4,6 @@ const {
 	assertEquals,
 	assertExists,
 	assertInstanceOf,
-	AssertionError,
 	assertNotEquals,
 	assertStrictEquals,
 } = stdAssert;
@@ -24,21 +23,9 @@ const DenoTestBase: ITestBase = {
 	assertInstanceOf,
 	assertNotEquals,
 	assertStrictEquals,
-	assertTrue: function (actual: boolean): void {
-		if (actual !== true) {
-			throw new AssertionError(`actual: "${actual}" expected to be true"`);
-		}
-	},
-	assertFalse(actual: boolean): void {
-		if (actual !== false) {
-			throw new AssertionError(`actual: "${actual}" expected to be false"`);
-		}
-	},
-	assertNull(actual: boolean): void {
-		if (actual !== null) {
-			throw new AssertionError(`actual: "${actual}" expected to be null"`);
-		}
-	},
+	assertTrue: (actual: boolean) => assertStrictEquals(actual, true),
+	assertFalse: (actual: boolean) => assertStrictEquals(actual, false),
+	assertNull: (actual: any) => assertEquals(actual, null),
 	testSuite,
 };