feat: Improved diff on apiVersion changes (databus23#73)

Resolves databus23#70

When the apiVersion of a Kind changes, helm-diff detects this as a
remove/readd of the whole manifest; this makes it difficult to see the
actual changes. This change enables a small heuristic so apiVersion
changes like `authentication.k8s.io/v1beta1` ->
`authentication.k8s.io/v1` show up as a one-line diff instead of a
full-manifest diff, while hopefully not meddling with unexpected
apiVersions too badly.

diff/diff_test.go

@@ -1,9 +1,13 @@
 package diff
 
 import (
-	"testing"
 	"bytes"
+	"testing"
+
 	"github.com/mgutz/ansi"
+	"github.com/stretchr/testify/require"
+
+	"github.com/databus23/helm-diff/manifest"
 )
 
 var text1 = "" +
@@ -121,3 +125,44 @@ func assertDiff(t *testing.T, before, after string, context int, expected string
 		t.Errorf("Unexpected diff output: \nExpected:\n#%v# \nActual:\n#%v#", expected, actual)
 	}
 }
+
+func TestDiffManifests(t *testing.T) {
+	specBeta := map[string]*manifest.MappingResult{
+		"default, nginx, Deployment (apps)": &manifest.MappingResult{
+
+			Name: "default, nginx, Deployment (apps)",
+			Kind: "Deployment",
+			Content: `
+apiVersion: apps/v1beta1
+kind: Deployment
+metadata:
+  name: nginx
+`,
+		}}
+
+	specRelease := map[string]*manifest.MappingResult{
+		"default, nginx, Deployment (apps)": &manifest.MappingResult{
+
+			Name: "default, nginx, Deployment (apps)",
+			Kind: "Deployment",
+			Content: `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx
+`,
+		}}
+
+	var buf bytes.Buffer
+	DiffManifests(specBeta, specRelease, []string{}, 10, &buf)
+
+	require.Equal(t, `default, nginx, Deployment (apps) has changed:
+  
+- apiVersion: apps/v1beta1
++ apiVersion: apps/v1
+  kind: Deployment
+  metadata:
+    name: nginx
+  
+`, buf.String())
+}

glide.yaml

@@ -15,3 +15,6 @@ import:
   version: 1.7.2
 - package: golang.org/x/net
   version: 1c05540f6879653db88113bc4a2b70aec4bd491f
+testImport:
+- package: github.com/stretchr/testify
+  version: ^1.2.2

manifest/parse.go

@@ -29,7 +29,13 @@ type metadata struct {
 }
 
 func (m metadata) String() string {
-	return fmt.Sprintf("%s, %s, %s (%s)", m.Metadata.Namespace, m.Metadata.Name, m.Kind, m.ApiVersion)
+	apiBase := m.ApiVersion
+	sp := strings.Split(apiBase, "/")
+	if len(sp) > 1 {
+		apiBase = strings.Join(sp[:len(sp)-1], "/")
+	}
+
+	return fmt.Sprintf("%s, %s, %s (%s)", m.Metadata.Namespace, m.Metadata.Name, m.Kind, apiBase)
 }
 
 func scanYamlSpecs(data []byte, atEOF bool) (advance int, token []byte, err error) {

manifest/parse_test.go

@@ -0,0 +1,60 @@
+package manifest_test
+
+import (
+	"io/ioutil"
+	"sort"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	. "github.com/databus23/helm-diff/manifest"
+)
+
+func foundObjects(result map[string]*MappingResult) []string {
+	objs := make([]string, 0, len(result))
+	for k, _ := range result {
+		objs = append(objs, k)
+	}
+	sort.Strings(objs)
+	return objs
+}
+
+func TestPod(t *testing.T) {
+	spec, err := ioutil.ReadFile("testdata/pod.yaml")
+	require.NoError(t, err)
+
+	require.Equal(t,
+		[]string{"default, nginx, Pod (v1)"},
+		foundObjects(Parse(string(spec), "default")),
+	)
+}
+
+func TestPodNamespace(t *testing.T) {
+	spec, err := ioutil.ReadFile("testdata/pod_namespace.yaml")
+	require.NoError(t, err)
+
+	require.Equal(t,
+		[]string{"batcave, nginx, Pod (v1)"},
+		foundObjects(Parse(string(spec), "default")),
+	)
+}
+
+func TestDeployV1(t *testing.T) {
+	spec, err := ioutil.ReadFile("testdata/deploy_v1.yaml")
+	require.NoError(t, err)
+
+	require.Equal(t,
+		[]string{"default, nginx, Deployment (apps)"},
+		foundObjects(Parse(string(spec), "default")),
+	)
+}
+
+func TestDeployV1Beta1(t *testing.T) {
+	spec, err := ioutil.ReadFile("testdata/deploy_v1beta1.yaml")
+	require.NoError(t, err)
+
+	require.Equal(t,
+		[]string{"default, nginx, Deployment (apps)"},
+		foundObjects(Parse(string(spec), "default")),
+	)
+}

manifest/testdata/deploy_v1.yaml

@@ -0,0 +1,22 @@
+
+---
+# Source: nginx/deployment.yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.7.9
+        ports:
+        - containerPort: 80

manifest/testdata/deploy_v1beta1.yaml

@@ -0,0 +1,22 @@
+
+---
+# Source: nginx/deployment.yaml
+apiVersion: apps/v1beta1
+kind: Deployment
+metadata:
+  name: nginx
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.7.9
+        ports:
+        - containerPort: 80

manifest/testdata/pod.yaml

@@ -0,0 +1,13 @@
+
+---
+# Source: nginx/pod.yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: nginx
+spec:
+  containers:
+  - name: nginx
+    image: nginx:1.7.9
+    ports:
+    - containerPort: 80

manifest/testdata/pod_namespace.yaml

@@ -0,0 +1,14 @@
+
+---
+# Source: nginx/pod.yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: nginx
+  namespace: batcave
+spec:
+  containers:
+  - name: nginx
+    image: nginx:1.7.9
+    ports:
+    - containerPort: 80