Re-add support for partial spec name filtering

No UI for this but users can construct URLs manually.
Fixes #2085.

spec/html/HtmlSpecFilterV2Spec.js

@@ -1,48 +1,69 @@
 describe('HtmlSpecFilterV2', function() {
-  it('matches everything when no string is provided', function() {
-    const specFilter = new privateUnderTest.HtmlSpecFilterV2({
-      filterString() {
-        return '';
-      }
-    });
+  describe('When both query parameters are falsy', function() {
+    it('matches everything', function() {
+      const specFilter = new privateUnderTest.HtmlSpecFilterV2({
+        filterParams() {
+          return { path: '', spec: '' };
+        }
+      });
 
-    expect(specFilter.matches({})).toBeTrue();
+      expect(specFilter.matches({})).toBeTrue();
+    });
   });
 
-  it('matches a spec with the exact same path', function() {
-    const specFilter = new privateUnderTest.HtmlSpecFilterV2({
-      filterString() {
-        return '["a","b","c"]';
-      }
+  describe('When the path parameter is truthy', function() {
+    it('matches a spec with the exact same path', function() {
+      const specFilter = new privateUnderTest.HtmlSpecFilterV2({
+        filterParams() {
+          return { path: '["a","b","c"]', spec: '' };
+        }
+      });
+
+      expect(specFilter.matches(stubSpec(['a', 'b', 'c']))).toBeTrue();
     });
 
-    expect(specFilter.matches(stubSpec(['a', 'b', 'c']))).toBeTrue();
-  });
+    it('matches a spec whose path has the filter path as a prefix', function() {
+      const specFilter = new privateUnderTest.HtmlSpecFilterV2({
+        filterParams() {
+          return { path: '["a","b"]', spec: '' };
+        }
+      });
 
-  it('matches a spec whose path has the filter path as a prefix', function() {
-    const specFilter = new privateUnderTest.HtmlSpecFilterV2({
-      filterString() {
-        return '["a","b"]';
-      }
+      expect(specFilter.matches(stubSpec(['a', 'b', 'c']))).toBeTrue();
     });
 
-    expect(specFilter.matches(stubSpec(['a', 'b', 'c']))).toBeTrue();
-  });
+    it('does not match a spec with a different path', function() {
+      const specFilter = new privateUnderTest.HtmlSpecFilterV2({
+        filterParams() {
+          return { path: '["a","b","c"]', spec: '' };
+        }
+      });
 
-  it('does not match a spec with a different path', function() {
-    const specFilter = new privateUnderTest.HtmlSpecFilterV2({
-      filterString() {
-        return '["a","b","c"]';
-      }
+      expect(specFilter.matches(stubSpec(['a', 'd', 'c']))).toBeFalse();
     });
-
-    expect(specFilter.matches(stubSpec(['a', 'd', 'c']))).toBeFalse();
   });
 
-  function stubSpec(path) {
+  describe('When the path parameter is falsy and the spec parameter is truthy', function() {
+    it('matches specs with full names containing the parameter value', function() {
+      const specFilter = new privateUnderTest.HtmlSpecFilterV2({
+        filterParams() {
+          return { path: '', spec: 'bar' };
+        }
+      });
+
+      expect(specFilter.matches(stubSpec('', 'foo bar baz'))).toBeTrue();
+      expect(specFilter.matches(stubSpec('', 'foo baz'))).toBeFalse();
+      expect(specFilter.matches(stubSpec('', 'sandbars'))).toBeTrue();
+    });
+  });
+
+  function stubSpec(path, fullName) {
     return {
       getPath() {
         return path;
+      },
+      getFullName() {
+        return fullName;
       }
     };
   }