test: run slow tests without race detector in CI (#338)

.github/workflows/ci.yml

@@ -19,8 +19,15 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: test & coverage report creation
+        # Some tests, notably TestRandomOperations, are extremely slow in CI
+        # with the race detector enabled, so we use -short when -race is
+        # enabled to reduce the number of slow tests, and then run without
+        # -short with -race disabled for a larger test set.
+        #
+        # We still run the same tests, just on smaller data sets with -short.
         run: |
-          go test ./... -mod=readonly -timeout 8m -race -coverprofile=coverage.txt -covermode=atomic
+          go test ./... -mod=readonly -timeout 5m -short -race -coverprofile=coverage.txt -covermode=atomic
+          go test ./... -mod=readonly -timeout 5m
       - uses: codecov/codecov-action@v1
         with:
           file: ./coverage.txt

export_test.go

@@ -171,23 +171,26 @@ func TestExporter(t *testing.T) {
 }
 
 func TestExporter_Import(t *testing.T) {
-	testcases := map[string]struct {
-		tree *ImmutableTree
-	}{
-		"empty tree":  {tree: NewImmutableTree(db.NewMemDB(), 0)},
-		"basic tree":  {tree: setupExportTreeBasic(t)},
-		"sized tree":  {tree: setupExportTreeSized(t, 4096)},
-		"random tree": {tree: setupExportTreeRandom(t)},
+	testcases := map[string]*ImmutableTree{
+		"empty tree": NewImmutableTree(db.NewMemDB(), 0),
+		"basic tree": setupExportTreeBasic(t),
 	}
-	for desc, tc := range testcases {
-		tc := tc // appease scopelint
+	if !testing.Short() {
+		testcases["sized tree"] = setupExportTreeSized(t, 4096)
+		testcases["random tree"] = setupExportTreeRandom(t)
+	}
+
+	for desc, tree := range testcases {
+		tree := tree
 		t.Run(desc, func(t *testing.T) {
-			exporter := tc.tree.Export()
+			t.Parallel()
+
+			exporter := tree.Export()
 			defer exporter.Close()
 
 			newTree, err := NewMutableTree(db.NewMemDB(), 0)
 			require.NoError(t, err)
-			importer, err := newTree.Import(tc.tree.Version())
+			importer, err := newTree.Import(tree.Version())
 			require.NoError(t, err)
 			defer importer.Close()
 
@@ -203,12 +206,12 @@ func TestExporter_Import(t *testing.T) {
 				require.NoError(t, err)
 			}
 
-			require.Equal(t, tc.tree.Hash(), newTree.Hash(), "Tree hash mismatch")
-			require.Equal(t, tc.tree.Size(), newTree.Size(), "Tree size mismatch")
-			require.Equal(t, tc.tree.Version(), newTree.Version(), "Tree version mismatch")
+			require.Equal(t, tree.Hash(), newTree.Hash(), "Tree hash mismatch")
+			require.Equal(t, tree.Size(), newTree.Size(), "Tree size mismatch")
+			require.Equal(t, tree.Version(), newTree.Version(), "Tree version mismatch")
 
-			tc.tree.Iterate(func(key, value []byte) bool {
-				index, _ := tc.tree.Get(key)
+			tree.Iterate(func(key, value []byte) bool {
+				index, _ := tree.Get(key)
 				newIndex, newValue := newTree.Get(key)
 				require.Equal(t, index, newIndex, "Index mismatch for key %v", key)
 				require.Equal(t, value, newValue, "Value mismatch for key %v", key)

tree_random_test.go

@@ -15,6 +15,8 @@ import (
 )
 
 func TestRandomOperations(t *testing.T) {
+	// In short mode (specifically, when running in CI with the race detector),
+	// we only run the first couple of seeds.
 	seeds := []int64{
 		498727689,
 		756509998,
@@ -28,9 +30,13 @@ func TestRandomOperations(t *testing.T) {
 		957382170,
 	}
 
-	for _, seed := range seeds {
-		seed := seed
+	for i, seed := range seeds {
+		i, seed := i, seed
 		t.Run(fmt.Sprintf("Seed %v", seed), func(t *testing.T) {
+			if testing.Short() && i >= 2 {
+				t.Skip("Skipping seed in short mode")
+			}
+			t.Parallel() // comment out to disable parallel tests, or use -parallel 1
 			testRandomOperations(t, seed)
 		})
 	}