Added error operator for custom validation #1259

pkg/yqlib/operator_error_test.go

@@ -0,0 +1,40 @@
+package yqlib
+
+import "testing"
+
+const validationExpression = `
+	with(env(numberOfCats); select(tag == "!!int") or error("numberOfCats is not a number :(")) | 
+	.numPets = env(numberOfCats)
+`
+
+var errorOperatorScenarios = []expressionScenario{
+	{
+		description:   "Validate a particular value",
+		document:      `a: hello`,
+		expression:    `select(.a == "howdy") or error(".a [" + .a + "] is not howdy!")`,
+		expectedError: ".a [hello] is not howdy!",
+	},
+	{
+		description:          "Validate the environment variable is a number - invalid",
+		environmentVariables: map[string]string{"numberOfCats": "please"},
+		expression:           `env(numberOfCats) | select(tag == "!!int") or error("numberOfCats is not a number :(")`,
+		expectedError:        "numberOfCats is not a number :(",
+	},
+	{
+		description:          "Validate the environment variable is a number - valid",
+		subdescription:       "`with` can be a convenient way of encapsulating validation.",
+		environmentVariables: map[string]string{"numberOfCats": "3"},
+		document:             "name: Bob\nfavouriteAnimal: cat\n",
+		expression:           validationExpression,
+		expected: []string{
+			"D0, P[], (doc)::name: Bob\nfavouriteAnimal: cat\nnumPets: 3\n",
+		},
+	},
+}
+
+func TestErrorOperatorScenarios(t *testing.T) {
+	for _, tt := range errorOperatorScenarios {
+		testScenario(t, &tt)
+	}
+	documentOperatorScenarios(t, "error", errorOperatorScenarios)
+}