add tests

pkg/yqlib/doc/operators/filter.md

@@ -1 +1,18 @@
 
+## Filter array
+Given a sample.yml file of:
+```yaml
+- 1
+- 2
+- 3
+```
+then
+```bash
+yq 'filter(. < 3)' sample.yml
+```
+will output
+```yaml
+- 1
+- 2
+```
+

pkg/yqlib/operator_filter_test.go

@@ -6,43 +6,39 @@ import (
 
 var filterOperatorScenarios = []expressionScenario{
 	{
-		skipDoc:    true,
+		description: "Filter array",
 		document:   `[1,2,3]`,
-		document2:  `[1, 2]`,
 		expression: `filter(. < 3)`,
 		expected: []string{
-			"D0, P[], (!!seq)::[2, 3, 4]\n",
-			"D0, P[], (!!seq)::[1, 2]\n",
-		},
-	},
-	/*
-	{
-		description: "Map array",
-		document:    `[1,2,3]`,
-		expression:  `map(. + 1)`,
-		expected: []string{
-			"D0, P[], (!!seq)::[2, 3, 4]\n",
+			"D0, P[], (!!seq)::- 1\n",
+			"D0, P[], (!!seq)::- 2\n",
 		},
 	},
 	{
 		skipDoc: true,
-		document:   `{a: 1, b: 2, c: 3}`,
-		document2:  `{x: 10, y: 20, z: 30}`,
-		expression: `map_values(. + 1)`,
+		document:    `[1,2,3]`,
+		expression:  `filter(. > 1)`,
 		expected: []string{
-			"D0, P[], (doc)::{a: 2, b: 3, c: 4}\n",
-			"D0, P[], (doc)::{x: 11, y: 21, z: 31}\n",
+			"D0, P[], (!!seq)::- 2\n",
+			"D0, P[], (!!seq)::- 3\n",
 		},
 	},
 	{
-		description: "Map object values",
-		document:    `{a: 1, b: 2, c: 3}`,
-		expression:  `map_values(. + 1)`,
+		skipDoc: true,
+		description: "Filter array to empty",
+		document:    `[1,2,3]`,
+		expression:  `filter(. > 4)`,
+		expected: []string{
+		},
+	},
+	{
+		skipDoc: true,
+		description: "Filter empty array",
+		document:    `[]`,
+		expression:  `filter(. > 1)`,
 		expected: []string{
-			"D0, P[], (doc)::{a: 2, b: 3, c: 4}\n",
 		},
 	},
-	*/
 }
 
 func TestFilterOperatorScenarios(t *testing.T) {