tests for partial match

pkg/policy/match_test.go

@@ -590,3 +590,80 @@ func TestOptionalSelectors(t *testing.T) {
 		})
 	}
 }
+
+// The unique behaviour of PartialMatch is that it should return true for missing non-optional data (unlike Match).
+func TestPartialMatch(t *testing.T) {
+	tests := []struct {
+		name          string
+		policy        Policy
+		data          interface{}
+		expectedMatch bool
+		expectedStmt  Statement
+	}{
+		{
+			name: "returns true for missing non-optional field",
+			policy: MustConstruct(
+				Equal(".field", literal.String("value")),
+			),
+			data:          map[string]interface{}{},
+			expectedMatch: true,
+			expectedStmt:  nil,
+		},
+		{
+			name: "returns true when present data matches",
+			policy: MustConstruct(
+				Equal(".foo", literal.String("correct")),
+				Equal(".missing", literal.String("whatever")),
+			),
+			data: map[string]interface{}{
+				"foo": "correct",
+			},
+			expectedMatch: true,
+			expectedStmt:  nil,
+		},
+		{
+			name: "returns false with failing statement for present but non-matching value",
+			policy: MustConstruct(
+				Equal(".foo", literal.String("value1")),
+				Equal(".bar", literal.String("value2")),
+			),
+			data: map[string]interface{}{
+				"foo": "wrong",
+				"bar": "value2",
+			},
+			expectedMatch: false,
+			expectedStmt: MustConstruct(
+				Equal(".foo", literal.String("value1")),
+			)[0],
+		},
+		{
+			name: "continues past missing data until finding actual mismatch",
+			policy: MustConstruct(
+				Equal(".missing", literal.String("value")),
+				Equal(".present", literal.String("wrong")),
+			),
+			data: map[string]interface{}{
+				"present": "actual",
+			},
+			expectedMatch: false,
+			expectedStmt: MustConstruct(
+				Equal(".present", literal.String("wrong")),
+			)[0],
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			node, err := literal.Map(tt.data)
+			assert.NoError(t, err)
+
+			match, stmt := tt.policy.PartialMatch(node)
+			assert.Equal(t, tt.expectedMatch, match)
+			if tt.expectedStmt == nil {
+				assert.Nil(t, stmt)
+			} else {
+				assert.Equal(t, tt.expectedStmt.Kind(), stmt.Kind())
+			}
+		})
+	}
+}