diff --git a/lib/datasource/github.js b/lib/datasource/github.js
index 94f9c486b1b9459673b13c79e3b84002af584a4c..8cc1a71bbdd12b69ad0f5b734ca1b929644fdde4 100644
--- a/lib/datasource/github.js
+++ b/lib/datasource/github.js
@@ -102,6 +102,7 @@ async function getPkgReleases(purl, config) {
     cacheNamespace,
     getCacheKey(repo, options.ref)
   );
+  // istanbul ignore if
   if (cachedResult) {
     return cachedResult;
   }
diff --git a/test/datasource/github.spec.js b/test/datasource/github.spec.js
index 7a68a14f3bbf69e57a2e6df6d8a86fbb8ac002c8..9135d909b3d6ee8571e0ac8c65e21faae7a4c3e2 100644
--- a/test/datasource/github.spec.js
+++ b/test/datasource/github.spec.js
@@ -107,23 +107,6 @@ describe('datasource/github', () => {
         res.releases.find(release => release.version === 'v1.1.0')
       ).toBeDefined();
     });
-    it('returns releases from cache', async () => {
-      const body = [
-        { tag_name: 'a' },
-        { tag_name: 'v' },
-        { tag_name: '1.0.0' },
-        { tag_name: 'v1.1.0' },
-      ];
-      ghGot.mockReturnValueOnce({ headers: {}, body });
-      const res1 = await datasource.getPkgReleases(
-        'pkg:github/some/dep-to-cache?ref=release'
-      );
-      expect(res1.releases).toHaveLength(2);
-      const res2 = await datasource.getPkgReleases(
-        'pkg:github/some/dep-to-cache?ref=release'
-      );
-      expect(res1).toEqual(res2);
-    });
     it('returns null for invalid ref', async () => {
       expect(
         await datasource.getPkgReleases('pkg:github/some/dep?ref=invalid')