test: add unit tests for links module

Covers link() and links() behavior: text preservation, fallback URL,
theme name acceptance for all builtin themes, and empty-text edge case.

Author: jdalton

test/unit/links.test.mts

@@ -0,0 +1,81 @@
+/**
+ * @fileoverview Unit tests for themed link utilities.
+ */
+
+import { describe, expect, it } from 'vitest'
+
+import { link, links } from '@socketsecurity/lib/links'
+
+describe('links', () => {
+  describe('link()', () => {
+    it('returns the link text (colored or not)', () => {
+      const output = link('Docs', 'https://socket.dev')
+      // Output should always include the text, optionally with ANSI codes.
+      expect(output).toContain('Docs')
+    })
+
+    it('appends url in parentheses when fallback is true', () => {
+      const output = link('Docs', 'https://socket.dev', { fallback: true })
+      expect(output).toContain('Docs')
+      expect(output).toContain('(https://socket.dev)')
+    })
+
+    it('omits url when fallback is false (default)', () => {
+      const output = link('Docs', 'https://socket.dev')
+      expect(output).not.toContain('https://socket.dev')
+    })
+
+    it('accepts a theme name string', () => {
+      const output = link('Docs', 'https://socket.dev', { theme: 'socket' })
+      expect(output).toContain('Docs')
+    })
+
+    it('accepts each builtin theme name without throwing', () => {
+      for (const name of [
+        'socket',
+        'sunset',
+        'terracotta',
+        'lush',
+        'ultra',
+      ] as const) {
+        const output = link('Docs', 'https://socket.dev', { theme: name })
+        expect(output).toContain('Docs')
+      }
+    })
+
+    it('works with empty text (may include ANSI reset sequences)', () => {
+      const output = link('', 'https://socket.dev')
+      // Empty text with no fallback produces only ANSI color codes around
+      // the (empty) text. Verify the url is not embedded in output.
+      expect(output).not.toContain('https://socket.dev')
+    })
+  })
+
+  describe('links()', () => {
+    it('returns one formatted output per input pair', () => {
+      const output = links([
+        ['Docs', 'https://socket.dev'],
+        ['API', 'https://api.socket.dev'],
+      ])
+      expect(output).toHaveLength(2)
+      expect(output[0]).toContain('Docs')
+      expect(output[1]).toContain('API')
+    })
+
+    it('respects the fallback option across all links', () => {
+      const output = links(
+        [
+          ['Docs', 'https://socket.dev'],
+          ['API', 'https://api.socket.dev'],
+        ],
+        { fallback: true },
+      )
+      expect(output[0]).toContain('(https://socket.dev)')
+      expect(output[1]).toContain('(https://api.socket.dev)')
+    })
+
+    it('returns an empty array for empty input', () => {
+      expect(links([])).toEqual([])
+    })
+  })
+})