add tests for delete operation, make it more forgiving in case user w…

…ants to delete a non-existing field

pkg/operations/delete.go

@@ -11,7 +11,9 @@ func Delete(root types.Node, path []string, args ...any) error {
 
 	node, err := root.Visit(path[0])
 
-	if err != nil {
+	if err == types.ErrFieldMissing {
+		return nil
+	} else if err != nil {
 		return err
 	}
 

pkg/operations/delete_test.go

@@ -0,0 +1,46 @@
+package operations
+
+import (
+	"testing"
+
+	"github.com/alecthomas/assert/v2"
+	"github.com/can3p/sackmesser/pkg/traverse/simplejson"
+)
+
+func TestDeleteOperation(t *testing.T) {
+	jstr := `{ "abc": { "def": [ 1, 2, 3 ] } }`
+
+	examples := []struct {
+		description string
+		path        []string
+		expected    string
+		isErr       bool
+	}{
+		{
+			description: "delete existing field",
+			path:        []string{"abc"},
+			expected:    `{}`,
+		},
+		{
+			description: "delete missing field is fine, it was deleted already",
+			path:        []string{"nonexistant"},
+			expected:    jstr,
+		},
+	}
+
+	for idx, ex := range examples {
+		node := simplejson.MustParse([]byte(jstr))
+
+		err := Delete(node, ex.path)
+
+		if ex.isErr {
+			assert.Error(t, err, "[Ex %d - %s]", idx+1, ex.description)
+			continue
+		}
+
+		expected := simplejson.MustParse([]byte(ex.expected))
+
+		assert.Equal(t, expected.Value(), node.Value(), "[Ex %d - %s]", idx+1, ex.description)
+	}
+
+}

pkg/traverse/simplejson/simplejson.go

@@ -224,6 +224,16 @@ func Parse(b []byte) (types.Node, error) {
 	}, nil
 }
 
+func MustParse(b []byte) types.Node {
+	n, err := Parse(b)
+
+	if err != nil {
+		panic(err)
+	}
+
+	return n
+}
+
 func FromNode(n types.Node) types.Node {
 	j := n.Value()