Adding more tests to prevent regression again :sweat

Author: mikefarah

pkg/yqlib/operator_add_test.go

@@ -317,6 +317,13 @@ var addOperatorScenarios = []expressionScenario{
 		expression:  `.[]  | (.a + "cat")`,
 		expected:    []string{},
 	},
+	{
+		skipDoc:     true,
+		description: "empty add shouldn't add",
+		document:    `[]`,
+		expression:  `.[]  | (.a + "cat" + .b)`,
+		expected:    []string{},
+	},
 	{
 		skipDoc:        true,
 		description:    "Add to empty",

pkg/yqlib/operator_map_test.go

@@ -15,6 +15,13 @@ var mapOperatorScenarios = []expressionScenario{
 			"D0, P[], (!!seq)::[6, 7, 8]\n",
 		},
 	},
+	{
+		skipDoc:    true,
+		expression: `[] | map(. + 42)`,
+		expected: []string{
+			"D0, P[], (!!seq)::[]\n",
+		},
+	},
 	{
 		skipDoc:    true,
 		document:   `[1,2]`,

pkg/yqlib/operator_select_test.go

@@ -5,6 +5,12 @@ import (
 )
 
 var selectOperatorScenarios = []expressionScenario{
+	{
+		skipDoc:    true,
+		document:   `cat: pants`,
+		expression: `select(.nope) | key + " why though?"`,
+		expected:   []string{},
+	},
 	{
 		skipDoc:    true,
 		document:   `cat`,