lib/resourcemerge: add extra merge testing

This aims to add some initial tests for EnvVar handling specifically,
to make sure we don't regress proxy.

Other unit tests should be added as we clean up the code.

Signed-off-by: Yu Qi Zhang <jerzhang@redhat.com>

lib/resourcemerge/core_test.go

@@ -0,0 +1,133 @@
+package resourcemerge
+
+import (
+	"fmt"
+	"testing"
+
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/equality"
+)
+
+// Test added for now to test ensureContainer (mostly so we don't break Env Vars - proxy)
+func TestEnsureContainer(t *testing.T) {
+	tests := []struct {
+		existing corev1.Container
+		input    corev1.Container
+
+		expectedModified bool
+		expected         corev1.Container
+	}{
+		// Change in proxy
+		{
+			existing: corev1.Container{
+				Env: []corev1.EnvVar{
+					{
+						Name:  "Proxy",
+						Value: "Proxy1",
+					},
+				},
+			},
+			input: corev1.Container{
+				Env: []corev1.EnvVar{
+					{
+						Name:  "Proxy",
+						Value: "Proxy2",
+					},
+				},
+			},
+			expectedModified: true,
+			expected: corev1.Container{
+				Env: []corev1.EnvVar{
+					{
+						Name:  "Proxy",
+						Value: "Proxy2",
+					},
+				},
+			},
+		},
+		// Add Proxy
+		{
+			existing: corev1.Container{
+				Env: []corev1.EnvVar{},
+			},
+			input: corev1.Container{
+				Env: []corev1.EnvVar{
+					{
+						Name:  "Proxy",
+						Value: "Proxy1",
+					},
+				},
+			},
+			expectedModified: true,
+			expected: corev1.Container{
+				Env: []corev1.EnvVar{
+					{
+						Name:  "Proxy",
+						Value: "Proxy1",
+					},
+				},
+			},
+		},
+		// Remove Proxy
+		{
+			existing: corev1.Container{
+				Env: []corev1.EnvVar{
+					{
+						Name:  "Proxy",
+						Value: "Proxy1",
+					},
+				},
+			},
+			input: corev1.Container{
+				Env: []corev1.EnvVar{},
+			},
+			expectedModified: true,
+			expected: corev1.Container{
+				Env: []corev1.EnvVar{},
+			},
+		},
+		// No change
+		{
+			existing: corev1.Container{
+				Env: []corev1.EnvVar{
+					{
+						Name:  "Proxy",
+						Value: "Proxy1",
+					},
+				},
+			},
+			input: corev1.Container{
+				Env: []corev1.EnvVar{
+					{
+						Name:  "Proxy",
+						Value: "Proxy1",
+					},
+				},
+			},
+			expectedModified: false,
+			expected: corev1.Container{
+				Env: []corev1.EnvVar{
+					{
+						Name:  "Proxy",
+						Value: "Proxy1",
+					},
+				},
+			},
+		},
+	}
+
+	for idx, test := range tests {
+		t.Run(fmt.Sprintf("test#%d", idx), func(t *testing.T) {
+			modified := BoolPtr(false)
+			ensureContainer(modified, &test.existing, test.input)
+
+			if *modified != test.expectedModified {
+				t.Fatalf("mismatch container got: %v want: %v", *modified, test.expectedModified)
+			}
+
+			if !equality.Semantic.DeepEqual(test.existing, test.expected) {
+				t.Fatalf("mismatch container got: %v want: %v", test.existing, test.expected)
+			}
+		})
+	}
+}