diff --git a/lib/tokenize/utils.test.ts b/lib/tokenize/utils.test.ts
index e69de29..01a3ce7 100644
--- a/lib/tokenize/utils.test.ts
+++ b/lib/tokenize/utils.test.ts
@@ -0,0 +1,116 @@
+import { assert, assertEquals } from "../../deps/std/testing.ts";
+import {
+  checkIsIdentifier,
+  checkIsInlineComment,
+  checkIsMultilineComment,
+  checkIsTextLiteral,
+  findInLexicon,
+} from "./utils.ts";
+import { LEXICON, Lexicon } from "./lexicon.ts";
+
+Deno.test("finds correct index in lexicon", () => {
+  const expectation = Lexicon.TypeDefiner;
+  const reality = findInLexicon("type", LEXICON);
+  assertEquals(expectation, reality);
+});
+
+Deno.test("returns null when not found (or null) in lexicon", () => {
+  const expectation = null;
+  const reality = findInLexicon("not_in_LEXICON", LEXICON);
+  assertEquals(expectation, reality);
+  assertEquals(expectation, findInLexicon(null, LEXICON));
+});
+
+Deno.test("correctly checks identifier", () => {
+  assert(checkIsIdentifier("good"));
+});
+
+Deno.test("correctly checks identifier (inner dots are good)", () => {
+  assert(checkIsIdentifier("inner.dots.are.good"));
+});
+
+Deno.test("correctly checks identifier ('_' is good)", () => {
+  assert(checkIsIdentifier("_underscores_are_chill_anywhere_"));
+});
+
+Deno.test("correctly checks identifier ('$' is good)", () => {
+  assert(checkIsIdentifier("$_is_good_anywhere_$_$"));
+});
+
+Deno.test("correctly checks identifier (caps are good)", () => {
+  assert(checkIsIdentifier("CAPS_are_good_ANYWHERE"));
+});
+
+Deno.test("correctly checks identifier (emojis are good)", () => {
+  assert(checkIsIdentifier("CAPS_are_good_ANYWHERE"));
+});
+
+Deno.test("correctly checks identifier (numbers are good)", () => {
+  assert(checkIsIdentifier("nums_are_good1234567890"));
+});
+
+Deno.test("correctly checks identifier (leading numbers are bad)", () => {
+  assert(!checkIsIdentifier("1leading_number_is_bad"));
+});
+
+Deno.test("correctly checks identifier (symbols are bad)", () => {
+  assert(!checkIsIdentifier("symbols_are_bad_Δ"));
+});
+
+Deno.test("correctly checks identifier (some special characters are bad)", () => {
+  assert(!checkIsIdentifier("bad!")); // contains '!'
+  assert(!checkIsIdentifier("bad@")); // contains '@'
+  assert(!checkIsIdentifier("bad#")); // contains '#'
+  assert(!checkIsIdentifier("bad^")); // contains '^'
+  assert(!checkIsIdentifier("bad&")); // contains '&'
+  assert(!checkIsIdentifier("bad*")); // contains '*'
+  assert(!checkIsIdentifier("bad|")); // contains '|'
+  assert(!checkIsIdentifier("bad+")); // contains '+'
+  assert(!checkIsIdentifier("bad=")); // contains '='
+});
+
+Deno.test("correctly checks identifier (outer dots are bad)", () => {
+  assert(!checkIsIdentifier(".outer.dots.are.bad."));
+});
+
+Deno.test("correctly checks identifier (hyphens are bad)", () => {
+  assert(!checkIsIdentifier("hyphens-are-bad"));
+});
+
+Deno.test("correctly checks text literal (with '`')", () => {
+  assert(checkIsTextLiteral("`example`"));
+});
+
+Deno.test('correctly checks text literal (with "\'")', () => {
+  assert(checkIsTextLiteral("'example'"));
+});
+
+Deno.test("correctly checks text literal (with '\"')", () => {
+  assert(checkIsTextLiteral('"example"'));
+});
+
+Deno.test("correctly checks text literal (multiline is good)", () => {
+  assert(
+    checkIsTextLiteral(`"example
+example
+example"`),
+  );
+});
+
+Deno.test("correctly checks text literal (non-matching quotes)", () => {
+  assert(!checkIsTextLiteral('"example`'));
+});
+
+Deno.test("correctly checks inline comment", () => {
+  assert(checkIsInlineComment("; example"));
+});
+
+Deno.test("correctly checks inline comment (not a comment)", () => {
+  assert(!checkIsInlineComment("example"));
+});
+
+Deno.test("correctly checks multiline comment", () => {
+  assert(checkIsMultilineComment(`/**
+ * example
+ */`));
+});
diff --git a/lib/tokenize/utils.ts b/lib/tokenize/utils.ts
index e4fd715..3eff223 100644
--- a/lib/tokenize/utils.ts
+++ b/lib/tokenize/utils.ts
@@ -14,15 +14,17 @@ export const findInLexicon = (
 };
 
 export const checkIsIdentifier = (candidate: string): boolean =>
-  /^[a-zA-Z_$]\.*[a-zA-Z_$0-9]*$/g.test(candidate);
+  /^[a-zA-Z_$][a-zA-Z0-9\._$]*$/.test(candidate);
 
-export const checkIsTextLiteral = (candidate: string): boolean =>
-  /^\`(.*?)\`$/g.test(candidate) ||
-  /^\'(.*?)\'$/g.test(candidate) ||
-  /^\"(.*?)\"$/g.test(candidate);
+export const checkIsTextLiteral = (candidate: string): boolean => {
+  return (candidate.startsWith("`") && candidate.endsWith("`")) ||
+    (candidate.startsWith("'") && candidate.endsWith("'")) ||
+    (candidate.startsWith('"') && candidate.endsWith('"'));
+};
 
 export const checkIsInlineComment = (candidate: string): boolean =>
-  /^;(.*?)$/.test(candidate);
+  candidate.startsWith(";");
 
-export const checkIsMultilineComment = (candidate: string): boolean =>
-  /^\/\*(.*?)\*\/$/.test(candidate);
+export const checkIsMultilineComment = (candidate: string): boolean => {
+  return candidate.startsWith("/*") && candidate.endsWith("*/");
+};