Fixed few coverage flakes (#872)

* blobtesting: coverage for GetMetadata() returning ErrNotFound
* content: additional direct coverage for diskCommittedContentIndexCache

internal/blobtesting/asserts.go

@@ -92,6 +92,16 @@ func AssertGetBlobNotFound(ctx context.Context, t testingT, s blob.Storage, blob
 	}
 }
 
+// AssertGetMetadataNotFound asserts that GetMetadata() for specified blobID returns ErrNotFound.
+func AssertGetMetadataNotFound(ctx context.Context, t testingT, s blob.Storage, blobID blob.ID) {
+	t.Helper()
+
+	_, err := s.GetMetadata(ctx, blobID)
+	if !errors.Is(err, blob.ErrBlobNotFound) {
+		t.Errorf("GetMetadata(%v) returned %v, %v but expected ErrNotFound", blobID, err)
+	}
+}
+
 // AssertListResults asserts that the list results with given prefix return the specified list of names in order.
 func AssertListResults(ctx context.Context, t testingT, s blob.Storage, prefix blob.ID, want ...blob.ID) {
 	t.Helper()

internal/blobtesting/verify.go

@@ -30,6 +30,7 @@ func VerifyStorage(ctx context.Context, t testingT, r blob.Storage) {
 	// First verify that blocks don't exist.
 	for _, b := range blocks {
 		AssertGetBlobNotFound(ctx, t, r, b.blk)
+		AssertGetMetadataNotFound(ctx, t, r, b.blk)
 	}
 
 	if err := r.DeleteBlob(ctx, "no-such-blob"); err != nil && !errors.Is(err, blob.ErrBlobNotFound) {

repo/content/committed_content_index_cache_test.go

@@ -59,6 +59,11 @@ func testCache(t *testing.T, cache committedContentIndexCache, fakeTime *faketim
 		"c4": &Info{PackBlobID: "p2345", ID: "c4"},
 	})))
 
+	must(t, cache.addContentToCache(ctx, "ndx2", mustBuildPackIndex(t, packIndexBuilder{
+		"c3": &Info{PackBlobID: "p2345", ID: "c3"},
+		"c4": &Info{PackBlobID: "p2345", ID: "c4"},
+	})))
+
 	ndx1, err := cache.openIndex(ctx, "ndx1")
 	must(t, err)