test(metadata): add explicit tests for slugger regexp replacements

src/generators/metadata/utils/__tests__/slugger.test.mjs

@@ -0,0 +1,118 @@
+'use strict';
+
+import assert from 'node:assert/strict';
+import { describe, it } from 'node:test';
+
+import createNodeSlugger, { slug } from '../slugger.mjs';
+
+const identity = str => str;
+
+describe('slug', () => {
+  describe('node.js replacement', () => {
+    it('replaces "node.js" with "nodejs"', () => {
+      assert.strictEqual(slug('node.js', identity), 'nodejs');
+    });
+
+    it('is case-insensitive', () => {
+      assert.strictEqual(slug('Node.JS', identity), 'nodejs');
+    });
+  });
+
+  describe('ampersand replacement', () => {
+    it('replaces & with -and-', () => {
+      assert.strictEqual(slug('a&b', identity), 'a-and-b');
+    });
+  });
+
+  describe('special character to hyphen replacement', () => {
+    it('replaces underscores with hyphens', () => {
+      assert.strictEqual(slug('foo_bar', identity), 'foo-bar');
+    });
+
+    it('replaces forward slashes with hyphens', () => {
+      assert.strictEqual(slug('foo/bar', identity), 'foo-bar');
+    });
+
+    it('replaces colons with hyphens', () => {
+      assert.strictEqual(slug('foo:bar', identity), 'foo-bar');
+    });
+
+    it('replaces commas with hyphens', () => {
+      assert.strictEqual(slug('foo,bar', identity), 'foo-bar');
+    });
+
+    it('replaces semicolons with hyphens', () => {
+      assert.strictEqual(slug('foo;bar', identity), 'foo-bar');
+    });
+  });
+
+  describe('leading hyphen removal', () => {
+    it('removes a single leading hyphen', () => {
+      assert.strictEqual(slug('-foo', identity), 'foo');
+    });
+
+    it('removes multiple leading hyphens', () => {
+      assert.strictEqual(slug('--foo', identity), 'foo');
+    });
+
+    it('preserves an all-hyphen string', () => {
+      assert.strictEqual(slug('---', identity), '---');
+    });
+  });
+
+  describe('trailing hyphen removal', () => {
+    it('removes a single trailing hyphen', () => {
+      assert.strictEqual(slug('foo-', identity), 'foo');
+    });
+
+    it('removes multiple trailing hyphens', () => {
+      assert.strictEqual(slug('foo--', identity), 'foo');
+    });
+  });
+
+  describe('consecutive hyphen replacement', () => {
+    it('replaces from start of string up to and including double-hyphen with a single hyphen', () => {
+      assert.strictEqual(slug('foo--bar', identity), '-bar');
+    });
+
+    it('does not fire on an all-hyphen string', () => {
+      assert.strictEqual(slug('---', identity), '---');
+    });
+  });
+
+  describe('integration with github-slugger', () => {
+    it('lowercases and hyphenates a plain title', () => {
+      assert.strictEqual(slug('Hello World'), 'hello-world');
+    });
+
+    it('converts underscored names to hyphenated slugs', () => {
+      assert.strictEqual(slug('child_process'), 'child-process');
+    });
+
+    it('handles titles with no special characters', () => {
+      assert.strictEqual(slug('stability index'), 'stability-index');
+    });
+  });
+});
+
+describe('createNodeSlugger', () => {
+  it('deduplicates the same slug by appending a counter', () => {
+    const slugger = createNodeSlugger();
+    assert.strictEqual(slugger.slug('Hello'), 'hello');
+    assert.strictEqual(slugger.slug('Hello'), 'hello-1');
+    assert.strictEqual(slugger.slug('Hello'), 'hello-2');
+  });
+
+  it('does not affect different titles', () => {
+    const slugger = createNodeSlugger();
+    assert.strictEqual(slugger.slug('First'), 'first');
+    assert.strictEqual(slugger.slug('Second'), 'second');
+  });
+
+  it('each instance has independent state', () => {
+    const slugger1 = createNodeSlugger();
+    const slugger2 = createNodeSlugger();
+    slugger1.slug('Hello');
+    assert.strictEqual(slugger2.slug('Hello'), 'hello');
+  });
+});