test: omit envoy golden test files that differ from the latest version

agent/xds/clusters_test.go

@@ -618,6 +618,7 @@ func TestClustersFromSnapshot(t *testing.T) {
 		},
 	}
 
+	latestEnvoyVersion := proxysupport.EnvoyVersions[0]
 	for _, envoyVersion := range proxysupport.EnvoyVersions {
 		sf, err := determineSupportedProxyFeaturesFromString(envoyVersion)
 		require.NoError(t, err)
@@ -660,7 +661,7 @@ func TestClustersFromSnapshot(t *testing.T) {
 						gName = tt.overrideGoldenName
 					}
 
-					require.JSONEq(goldenEnvoy(t, filepath.Join("clusters", gName), envoyVersion, gotJSON), gotJSON)
+					require.JSONEq(goldenEnvoy(t, filepath.Join("clusters", gName), envoyVersion, latestEnvoyVersion, gotJSON), gotJSON)
 				})
 			}
 		})
@@ -818,15 +819,15 @@ func setupTLSRootsAndLeaf(t *testing.T, snap *proxycfg.ConfigSnapshot) {
 	if snap.Leaf() != nil {
 		switch snap.Kind {
 		case structs.ServiceKindConnectProxy:
-			snap.ConnectProxy.Leaf.CertPEM = golden(t, "test-leaf-cert", "", "")
-			snap.ConnectProxy.Leaf.PrivateKeyPEM = golden(t, "test-leaf-key", "", "")
+			snap.ConnectProxy.Leaf.CertPEM = loadTestResource(t, "test-leaf-cert")
+			snap.ConnectProxy.Leaf.PrivateKeyPEM = loadTestResource(t, "test-leaf-key")
 		case structs.ServiceKindIngressGateway:
-			snap.IngressGateway.Leaf.CertPEM = golden(t, "test-leaf-cert", "", "")
-			snap.IngressGateway.Leaf.PrivateKeyPEM = golden(t, "test-leaf-key", "", "")
+			snap.IngressGateway.Leaf.CertPEM = loadTestResource(t, "test-leaf-cert")
+			snap.IngressGateway.Leaf.PrivateKeyPEM = loadTestResource(t, "test-leaf-key")
 		}
 	}
 	if snap.Roots != nil {
-		snap.Roots.Roots[0].RootCert = golden(t, "test-root-cert", "", "")
+		snap.Roots.Roots[0].RootCert = loadTestResource(t, "test-root-cert")
 	}
 }
 

agent/xds/endpoints_test.go

@@ -557,6 +557,7 @@ func Test_endpointsFromSnapshot(t *testing.T) {
 		},
 	}
 
+	latestEnvoyVersion := proxysupport.EnvoyVersions[0]
 	for _, envoyVersion := range proxysupport.EnvoyVersions {
 		sf, err := determineSupportedProxyFeaturesFromString(envoyVersion)
 		require.NoError(t, err)
@@ -599,7 +600,7 @@ func Test_endpointsFromSnapshot(t *testing.T) {
 						gName = tt.overrideGoldenName
 					}
 
-					require.JSONEq(goldenEnvoy(t, filepath.Join("endpoints", gName), envoyVersion, gotJSON), gotJSON)
+					require.JSONEq(goldenEnvoy(t, filepath.Join("endpoints", gName), envoyVersion, latestEnvoyVersion, gotJSON), gotJSON)
 				})
 			}
 		})

agent/xds/golden_test.go

@@ -4,6 +4,7 @@ import (
 	"flag"
 	"fmt"
 	"io/ioutil"
+	"os"
 	"path/filepath"
 	"testing"
 
@@ -18,9 +19,32 @@ import (
 // update allows golden files to be updated based on the current output.
 var update = flag.Bool("update", false, "update golden files")
 
+// goldenSimple is just for read/write access to a golden file that is not
+// envoy specific.
+func goldenSimple(t *testing.T, name, got string) string {
+	return golden(t, name, "", "", got)
+}
+
 // goldenEnvoy is a special variant of golden() that silos each named test by
 // each supported envoy version
-func goldenEnvoy(t *testing.T, name, envoyVersion, got string) string {
+func goldenEnvoy(t *testing.T, name, envoyVersion, latestEnvoyVersion, got string) string {
+	t.Helper()
+
+	require.NotEmpty(t, envoyVersion)
+
+	// We'll need both the name of this golden file for the requested version
+	// of envoy AND the latest version of envoy due to how the golden file
+	// coalescing works below when there is no xDS generated skew across envoy
+	// versions.
+	subname := goldenEnvoyVersionName(t, envoyVersion)
+	latestSubname := goldenEnvoyVersionName(t, latestEnvoyVersion)
+
+	return golden(t, name, subname, latestSubname, got)
+}
+
+func goldenEnvoyVersionName(t *testing.T, envoyVersion string) string {
+	t.Helper()
+
 	require.NotEmpty(t, envoyVersion)
 
 	// We do version sniffing on the complete version, but only generate
@@ -29,14 +53,26 @@ func goldenEnvoy(t *testing.T, name, envoyVersion, got string) string {
 	segments := version.Segments()
 	require.Len(t, segments, 3)
 
-	subname := fmt.Sprintf("envoy-%d-%d-x", segments[0], segments[1])
-
-	return golden(t, name, subname, got)
+	return fmt.Sprintf("envoy-%d-%d-x", segments[0], segments[1])
 }
 
 // golden reads and optionally writes the expected data to the golden file,
 // returning the contents as a string.
-func golden(t *testing.T, name, subname, got string) string {
+//
+// The golden file is named with two components the "name" and the "subname".
+// In the common case of xDS tests the "name" component is the logical name of
+// the test itself, and the "subname" is derived from the envoy major version.
+//
+// If latestSubname is specified we use that as a fallback source of comparison
+// if the specific golden file referred to by subname is absent.
+//
+// If the -update flag is passed when executing the tests then the contents of
+// the "got" argument are written to the golden file on disk. If the
+// latestSubname argument is specified in this mode and the generated content
+// matches that of the latest generated content then the specific golden file
+// referred to by 'subname' is deleted to avoid unnecessary duplication in the
+// testdata directory.
+func golden(t *testing.T, name, subname, latestSubname, got string) string {
 	t.Helper()
 
 	suffix := ".golden"
@@ -45,14 +81,52 @@ func golden(t *testing.T, name, subname, got string) string {
 	}
 
 	golden := filepath.Join("testdata", name+suffix)
-	if *update && got != "" {
-		err := ioutil.WriteFile(golden, []byte(got), 0644)
+
+	// Always load the latest golden file if configured to do so.
+	latestExpected := ""
+	if latestSubname != "" && subname != latestSubname {
+		latestGolden := filepath.Join("testdata", fmt.Sprintf("%s.%s.golden", name, latestSubname))
+		raw, err := ioutil.ReadFile(latestGolden)
 		require.NoError(t, err)
+		latestExpected = string(raw)
+	}
+
+	// Handle easy updates to the golden files in the agent/xds/testdata
+	// directory.
+	//
+	// To trim down PRs, we only create per-version golden files if they differ
+	// from the latest version.
+	if *update && got != "" {
+		if latestExpected == got {
+			// In update mode we erase a golden file if it is identical to
+			// the golden file corresponding to the latest version of
+			// envoy.
+			err := os.Remove(golden)
+			if err != nil && !os.IsNotExist(err) {
+				require.NoError(t, err)
+			}
+			return got
+		}
+
+		require.NoError(t, ioutil.WriteFile(golden, []byte(got), 0644))
+		return got
 	}
 
 	expected, err := ioutil.ReadFile(golden)
+	if latestExpected != "" && os.IsNotExist(err) {
+		// In readonly mode if a specific golden file isn't found, we fallback
+		// on the latest one.
+		return latestExpected
+	}
 	require.NoError(t, err)
+	return string(expected)
+}
 
+func loadTestResource(t *testing.T, name string) string {
+	t.Helper()
+
+	expected, err := ioutil.ReadFile(filepath.Join("testdata", name+".golden"))
+	require.NoError(t, err)
 	return string(expected)
 }
 

agent/xds/listeners_test.go

@@ -478,6 +478,7 @@ func TestListenersFromSnapshot(t *testing.T) {
 		},
 	}
 
+	latestEnvoyVersion := proxysupport.EnvoyVersions[0]
 	for _, envoyVersion := range proxysupport.EnvoyVersions {
 		sf, err := determineSupportedProxyFeaturesFromString(envoyVersion)
 		require.NoError(t, err)
@@ -527,7 +528,7 @@ func TestListenersFromSnapshot(t *testing.T) {
 						gName = tt.overrideGoldenName
 					}
 
-					require.JSONEq(goldenEnvoy(t, filepath.Join("listeners", gName), envoyVersion, gotJSON), gotJSON)
+					require.JSONEq(goldenEnvoy(t, filepath.Join("listeners", gName), envoyVersion, latestEnvoyVersion, gotJSON), gotJSON)
 				})
 			}
 		})

agent/xds/rbac_test.go

@@ -250,15 +250,15 @@ func TestMakeRBACNetworkAndHTTPFilters(t *testing.T) {
 
 				gotJSON := protoToJSON(t, filter)
 
-				require.JSONEq(t, golden(t, filepath.Join("rbac", name), "", gotJSON), gotJSON)
+				require.JSONEq(t, goldenSimple(t, filepath.Join("rbac", name), gotJSON), gotJSON)
 			})
 			t.Run("http filter", func(t *testing.T) {
 				filter, err := makeRBACHTTPFilter(tt.intentions, tt.intentionDefaultAllow)
 				require.NoError(t, err)
 
 				gotJSON := protoToJSON(t, filter)
 
-				require.JSONEq(t, golden(t, filepath.Join("rbac", name+"--httpfilter"), "", gotJSON), gotJSON)
+				require.JSONEq(t, goldenSimple(t, filepath.Join("rbac", name+"--httpfilter"), gotJSON), gotJSON)
 			})
 		})
 	}

agent/xds/routes_test.go

@@ -238,6 +238,7 @@ func TestRoutesFromSnapshot(t *testing.T) {
 		},
 	}
 
+	latestEnvoyVersion := proxysupport.EnvoyVersions[0]
 	for _, envoyVersion := range proxysupport.EnvoyVersions {
 		sf, err := determineSupportedProxyFeaturesFromString(envoyVersion)
 		require.NoError(t, err)
@@ -278,7 +279,7 @@ func TestRoutesFromSnapshot(t *testing.T) {
 						gName = tt.overrideGoldenName
 					}
 
-					require.JSONEq(goldenEnvoy(t, filepath.Join("routes", gName), envoyVersion, gotJSON), gotJSON)
+					require.JSONEq(goldenEnvoy(t, filepath.Join("routes", gName), envoyVersion, latestEnvoyVersion, gotJSON), gotJSON)
 				})
 			}
 		})