featureset: Add tests for feature sets

The featureset helper currently doesn't have any tests, but it has grown
to be a widely used helper which did have bugs. This commit adds a few
tests to verify it behaves as expected.

1 files changed, 154 insertions, 0 deletions

diff --git a/internal/testhelper/featureset_test.go b/internal/testhelper/featureset_test.go
new file mode 100644
index 000000000..fc6fa0f60
--- /dev/null
+++ b/internal/testhelper/featureset_test.go
@@ -0,0 +1,154 @@
+package testhelper
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"gitlab.com/gitlab-org/gitaly/internal/helper"
+	ff "gitlab.com/gitlab-org/gitaly/internal/metadata/featureflag"
+)
+
+func features(flag ...ff.FeatureFlag) map[ff.FeatureFlag]struct{} {
+	features := make(map[ff.FeatureFlag]struct{}, len(flag))
+	for _, f := range flag {
+		features[f] = struct{}{}
+	}
+	return features
+}
+
+func TestNewFeatureSets(t *testing.T) {
+	testcases := []struct {
+		desc         string
+		features     []ff.FeatureFlag
+		rubyFeatures []ff.FeatureFlag
+		expected     FeatureSets
+	}{
+		{
+			desc:     "single Go feature flag",
+			features: []ff.FeatureFlag{ff.GoFetchSourceBranch},
+			expected: FeatureSets{
+				FeatureSet{
+					features:     features(),
+					rubyFeatures: features(),
+				},
+				FeatureSet{
+					features:     features(ff.GoFetchSourceBranch),
+					rubyFeatures: features(),
+				},
+			},
+		},
+		{
+			desc:     "two Go feature flags",
+			features: []ff.FeatureFlag{ff.GoFetchSourceBranch, ff.DistributedReads},
+			expected: FeatureSets{
+				FeatureSet{
+					features:     features(),
+					rubyFeatures: features(),
+				},
+				FeatureSet{
+					features:     features(ff.DistributedReads),
+					rubyFeatures: features(),
+				},
+				FeatureSet{
+					features:     features(ff.GoFetchSourceBranch),
+					rubyFeatures: features(),
+				},
+				FeatureSet{
+					features:     features(ff.DistributedReads, ff.GoFetchSourceBranch),
+					rubyFeatures: features(),
+				},
+			},
+		},
+		{
+			desc:         "single Ruby feature flag",
+			rubyFeatures: []ff.FeatureFlag{ff.GoFetchSourceBranch},
+			expected: FeatureSets{
+				FeatureSet{
+					features:     features(),
+					rubyFeatures: features(),
+				},
+				FeatureSet{
+					features:     features(),
+					rubyFeatures: features(ff.GoFetchSourceBranch),
+				},
+			},
+		},
+		{
+			desc:         "two Ruby feature flags",
+			rubyFeatures: []ff.FeatureFlag{ff.GoFetchSourceBranch, ff.DistributedReads},
+			expected: FeatureSets{
+				FeatureSet{
+					features:     features(),
+					rubyFeatures: features(),
+				},
+				FeatureSet{
+					features:     features(),
+					rubyFeatures: features(ff.DistributedReads),
+				},
+				FeatureSet{
+					features:     features(),
+					rubyFeatures: features(ff.GoFetchSourceBranch),
+				},
+				FeatureSet{
+					features:     features(),
+					rubyFeatures: features(ff.DistributedReads, ff.GoFetchSourceBranch),
+				},
+			},
+		},
+		{
+			desc:         "Go and Ruby feature flag",
+			features:     []ff.FeatureFlag{ff.DistributedReads},
+			rubyFeatures: []ff.FeatureFlag{ff.GoFetchSourceBranch},
+			expected: FeatureSets{
+				FeatureSet{
+					features:     features(),
+					rubyFeatures: features(),
+				},
+				FeatureSet{
+					features:     features(ff.DistributedReads),
+					rubyFeatures: features(),
+				},
+				FeatureSet{
+					features:     features(),
+					rubyFeatures: features(ff.GoFetchSourceBranch),
+				},
+				FeatureSet{
+					features:     features(ff.DistributedReads),
+					rubyFeatures: features(ff.GoFetchSourceBranch),
+				},
+			},
+		},
+	}
+
+	for _, tc := range testcases {
+		t.Run(tc.desc, func(t *testing.T) {
+			featureSets := NewFeatureSets(tc.features, tc.rubyFeatures...)
+			require.Len(t, featureSets, len(tc.expected))
+			for _, expected := range tc.expected {
+				require.Contains(t, featureSets, expected)
+			}
+		})
+	}
+}
+
+func TestFeatureSets_Run(t *testing.T) {
+	var flags [][2]bool
+
+	NewFeatureSets([]ff.FeatureFlag{
+		ff.DistributedReads, ff.GoFetchSourceBranch,
+	}).Run(t, func(t *testing.T, ctx context.Context) {
+		ctx = helper.OutgoingToIncoming(ctx)
+		flags = append(flags, [2]bool{
+			ff.IsDisabled(ctx, ff.DistributedReads),
+			ff.IsDisabled(ctx, ff.GoFetchSourceBranch),
+		})
+	})
+
+	require.Equal(t, flags, [][2]bool{
+		{false, false},
+		{true, false},
+		{false, true},
+		{true, true},
+	})
+}