Add and update tests around diamond import of folders.

1. Test simple import of common resources.
2. Test simple import of common variables.
3. Test simple import of variables without their target
   resources in the parent folders.
4. Test that the algorithm is reporting proper errors
   in case of not supported diamond import of resources.
5. Test that the algorithm is reporting proper errors
   in case of not supported diamond import of variables.
6. Update errors messages in existing tests.

pkg/target/complexcomposition_test.go

@@ -224,7 +224,7 @@ resources:
 		t.Fatalf("Expected resource accumulation error")
 	}
 	if !strings.Contains(
-		err.Error(), "already registered id: apps_v1_StatefulSet|~X|my-sts") {
+		err.Error(), "conflict between") {
 		t.Fatalf("Unexpected err: %v", err)
 	}
 
@@ -283,7 +283,7 @@ resources:
 		t.Fatalf("Expected resource accumulation error")
 	}
 	if !strings.Contains(
-		err.Error(), "already registered id: apps_v1_StatefulSet|~X|my-sts") {
+		err.Error(), "conflict between") {
 		t.Fatalf("Unexpected err: %v", err)
 	}
 

pkg/target/diamondcomposition_test.go

@@ -62,17 +62,49 @@ func writeDeploymentBase(th *kusttest_test.KustTestHarness) {
 	th.WriteK("/app/base", `
 resources:
 - deployment.yaml
+patchesStrategicMerge:
+- dep-patch.yaml
 `)
 
 	th.WriteF("/app/base/deployment.yaml", `
 apiVersion: apps/v1
 kind: Deployment
+metadata:
+  name: my-deployment
+spec:
+  template:
+    spec:
+      containers:
+      - name: my-deployment
+        image: my-image
+`)
+
+	th.WriteF("/app/base/dep-patch.yaml", `
+apiVersion: apps/v1
+kind: Deployment
 metadata:
   name: my-deployment
 spec:
   template:
     spec:
       dnsPolicy: "None"
+`)
+}
+
+func writeDeploymentBaseNoPatch(th *kusttest_test.KustTestHarness) {
+	th.WriteK("/app/base", `
+resources:
+- deployment.yaml
+`)
+
+	th.WriteF("/app/base/deployment.yaml", `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: my-deployment
+spec:
+  template:
+    spec:
       containers:
       - name: my-deployment
         image: my-image
@@ -122,7 +154,11 @@ patchesStrategicMerge:
 //          \     |     /
 //              base
 //
-func TestIssue1251_CompositeDiamond_Failure(t *testing.T) {
+
+// In the case, the DeploymentBase is setting the DnsPolicy to None.
+// Kustomize detects a merge conflict when merging probe, dns and restart
+// into composite.
+func TestIssue1251_CompositeDiamond_ProbeDnsRestart_MergeConflict(t *testing.T) {
 	th := kusttest_test.NewKustTestHarness(t, "/app/composite")
 	writeDeploymentBase(th)
 	writeProbeOverlay(th)
@@ -141,7 +177,55 @@ resources:
 		t.Fatalf("Expected resource accumulation error")
 	}
 	if !strings.Contains(
-		err.Error(), "already registered id: apps_v1_Deployment|~X|my-deployment") {
+		err.Error(), "conflict between") {
+		t.Fatalf("Unexpected err: %v", err)
+	}
+}
+
+func TestIssue1251_CompositeDiamond_ProbeRestartDns_MergeConflict(t *testing.T) {
+	th := kusttest_test.NewKustTestHarness(t, "/app/composite")
+	writeDeploymentBase(th)
+	writeProbeOverlay(th)
+	writeDNSOverlay(th)
+	writeRestartOverlay(th)
+
+	th.WriteK("/app/composite", `
+resources:
+- ../probe
+- ../restart
+- ../dns
+`)
+
+	_, err := th.MakeKustTarget().MakeCustomizedResMap()
+	if err == nil {
+		t.Fatalf("Expected resource accumulation error")
+	}
+	if !strings.Contains(
+		err.Error(), "conflict between") {
+		t.Fatalf("Unexpected err: %v", err)
+	}
+}
+
+func TestIssue1251_CompositeDiamond_DnsProbeRestart_MergeConflict(t *testing.T) {
+	th := kusttest_test.NewKustTestHarness(t, "/app/composite")
+	writeDeploymentBase(th)
+	writeProbeOverlay(th)
+	writeDNSOverlay(th)
+	writeRestartOverlay(th)
+
+	th.WriteK("/app/composite", `
+resources:
+- ../dns
+- ../probe
+- ../restart
+`)
+
+	_, err := th.MakeKustTarget().MakeCustomizedResMap()
+	if err == nil {
+		t.Fatalf("Expected resource accumulation error")
+	}
+	if !strings.Contains(
+		err.Error(), "conflict between") {
 		t.Fatalf("Unexpected err: %v", err)
 	}
 }
@@ -165,6 +249,51 @@ spec:
       restartPolicy: Always
 `
 
+// Same test except that there no conflict to be detected in during
+// the merge
+func TestIssue1251_CompositeDiamond_ProbeRestartDns(t *testing.T) {
+	th := kusttest_test.NewKustTestHarness(t, "/app/composite")
+	writeDeploymentBaseNoPatch(th)
+	writeProbeOverlay(th)
+	writeDNSOverlay(th)
+	writeRestartOverlay(th)
+
+	th.WriteK("/app/composite", `
+resources:
+- ../probe
+- ../dns
+- ../restart
+`)
+
+	m, err := th.MakeKustTarget().MakeCustomizedResMap()
+	if err != nil {
+		t.Fatalf("Err: %v", err)
+	}
+	th.AssertActualEqualsExpected(m, expectedPatchedDeployment)
+}
+
+// Identical test. Validate that ordering of resources as no effect.
+func TestIssue1251_CompositeDiamond_ProbeDnsRestart(t *testing.T) {
+	th := kusttest_test.NewKustTestHarness(t, "/app/composite")
+	writeDeploymentBaseNoPatch(th)
+	writeProbeOverlay(th)
+	writeDNSOverlay(th)
+	writeRestartOverlay(th)
+
+	th.WriteK("/app/composite", `
+resources:
+- ../probe
+- ../restart
+- ../dns
+`)
+
+	m, err := th.MakeKustTarget().MakeCustomizedResMap()
+	if err != nil {
+		t.Fatalf("Err: %v", err)
+	}
+	th.AssertActualEqualsExpected(m, expectedPatchedDeployment)
+}
+
 // This test reuses some methods from TestIssue1251_CompositeDiamond,
 // but overwrites the kustomization files in the overlays.
 func TestIssue1251_Patches_Overlayed(t *testing.T) {