Start supporting strategic merge patch in kyaml merge2.

kyaml/yaml/merge2/smpdirective_test.go

@@ -0,0 +1,112 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+package merge2
+
+import (
+	"strings"
+	"testing"
+
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+func Test_determineSmpDirective(t *testing.T) {
+	var cases = map[string]struct {
+		patch       string
+		elided      string
+		expected    smpDirective
+		errExpected string
+	}{
+		`scalar`: {
+			patch:       "dumb",
+			expected:    smpMerge,
+			errExpected: "no implemented strategic merge patch strategy",
+		},
+		`list merge`: {
+			patch: `
+- one
+- two
+- three
+`,
+			expected: smpMerge,
+			elided: `- one
+- two
+- three
+`,
+		},
+		`map replace`: {
+			patch: `
+metal: heavy
+$patch: replace
+veggie: carrot
+`,
+			expected: smpReplace,
+			elided: `metal: heavy
+veggie: carrot
+`,
+		},
+		`map delete`: {
+			patch: `
+metal: heavy
+$patch: delete
+veggie: carrot
+`,
+			expected: smpDelete,
+			elided: `metal: heavy
+veggie: carrot
+`,
+		},
+		`map merge`: {
+			patch: `
+metal: heavy
+$patch: merge
+veggie: carrot
+`,
+			expected: smpMerge,
+			elided: `metal: heavy
+veggie: carrot
+`,
+		},
+		`map default`: {
+			patch: `
+metal: heavy
+veggie: carrot
+`,
+			expected: smpMerge,
+			elided: `metal: heavy
+veggie: carrot
+`,
+		},
+	}
+
+	for n := range cases {
+		tc := cases[n]
+		t.Run(n, func(t *testing.T) {
+			p, err := yaml.Parse(tc.patch)
+			if err != nil {
+				t.Fatalf("unexpected parse err %v", err)
+			}
+			unwrapped := yaml.NewRNode(p.YNode())
+			actual, err := determineSmpDirective(unwrapped)
+			if err == nil {
+				if tc.errExpected != "" {
+					t.Fatalf("should have seen an error")
+				}
+				if tc.expected != actual {
+					t.Fatalf("expected %s, got %s", tc.expected, actual)
+				}
+				if tc.elided != unwrapped.MustString() {
+					t.Fatalf(
+						"expected %s, got %s",
+						tc.elided, unwrapped.MustString())
+				}
+			} else {
+				if tc.errExpected == "" {
+					t.Fatalf("unexpected err: %v", err)
+				}
+				if !strings.Contains(err.Error(), tc.errExpected) {
+					t.Fatalf("expected some error other than:  %v", err)
+				}
+			}
+		})
+	}
+}