Added tests for tag name extraction from tag links & search queries

src/lib/philomena/tag-utils.ts

@@ -42,7 +42,7 @@ const tagLinkRegExp = /\/tags\/(?<encodedTagName>[^/?#]+)/;
  *
  * @see https://github.com/philomena-dev/philomena/blob/6086757b654da8792ae52adb2a2f501ea6c30d12/lib/philomena/slug.ex#L52-L57
  */
-const slugEncodedCharacters: Map<string, string> = new Map([
+export const slugEncodedCharacters: Map<string, string> = new Map([
   ['-dash-', '-'],
   ['-fwslash-', '/'],
   ['-bwslash-', '\\'],

tests/lib/philomena/tag-utils.spec.ts

@@ -0,0 +1,73 @@
+import { describe, expect, it } from 'vitest';
+import { URL } from 'url';
+import { resolveTagNameFromLink, slugEncodedCharacters } from '$lib/philomena/tag-utils';
+
+describe('tag-utils', () => {
+  const origin = 'https://furbooru.org';
+
+  describe('resolveTagNameFromLink', () => {
+    function resolveFromSearchQuery(encodedQuery: string): string | null {
+      return resolveTagNameFromLink(new URL(`/search?q=${encodedQuery}`, origin));
+    }
+
+    describe('Parsing from /search/?q=tag links', () => {
+      // Test cases for tags separated by commas
+      it('should resolve a single tag from /search URLs', () => {
+        expect(resolveFromSearchQuery('safe')).toBe('safe');
+      });
+
+      it('should return null for queries with multiple comma-separated tags', () => {
+        // Comma acts as a separator in the query, resulting in multiple tokens
+        expect(resolveFromSearchQuery('safe, suggestive')).toBe(null);
+      });
+
+      it('should properly treat parentheses in the query with single tag', () => {
+        // Parentheses are operators in the query language, but when inside the tag name, they should still be properly
+        // working.
+        expect(resolveFromSearchQuery('experiment (casualties unknown)')).toBe('experiment (casualties unknown)');
+      });
+
+      it('should properly resolve queries with encoded characters', () => {
+        expect(resolveFromSearchQuery('pok%C3%A9mon')).toBe('pokémon');
+      });
+
+      it('should unquote quoted term', () => {
+        expect(resolveFromSearchQuery('"experiment (casualties unknown)"')).toBe('experiment (casualties unknown)')
+        expect(resolveFromSearchQuery('"single tag, really"')).toBe('single tag, really');
+      });
+    })
+
+    describe('Parsing from /tags/name links', () => {
+      function resolveFromTagLink(encodedTagName: string): string | null {
+        return resolveTagNameFromLink(new URL(`/tags/${encodedTagName}`, origin));
+      }
+
+      it('should resolve a single tag', () => {
+        expect(resolveFromTagLink('safe')).toBe('safe');
+      });
+
+      it('should only read the tag page even if query is provided', () => {
+        expect(resolveFromTagLink('grotesque?q=explicit')).toBe('grotesque');
+      });
+
+      it('should properly resolve links with encoded characters', () => {
+        expect(resolveFromTagLink('pok%C3%A9mon')).toBe('pokémon');
+      });
+
+      it('should decoded slug-encoded characters', () => {
+        // More common example where tag is.
+        expect(resolveFromTagLink(`namespace-colon-tag+name`)).toBe('namespace:tag name');
+
+        // Testing the whole list of encoded characters.
+        for (const [encodedCharacter, decodedCharacter] of slugEncodedCharacters.entries()) {
+          expect(resolveFromTagLink(`test+symbol${encodedCharacter}without+spaces`)).toBe(`test symbol${decodedCharacter}without spaces`);
+          expect(resolveFromTagLink(`test+symbol+${encodedCharacter}+with+spaces`)).toBe(`test symbol ${decodedCharacter} with spaces`);
+        }
+      });
+    });
+
+    it('should return null for unsupported URLs', () => {
+      expect(resolveTagNameFromLink(new URL('/pages/example', origin))).toBe(null);
+    });
+  });
+});