Add tests for prefix function

Author: breml

ast/ast_helper_test.go

@@ -0,0 +1,79 @@
+package ast
+
+import "testing"
+
+func TestPrefix(t *testing.T) {
+	tt := []struct {
+		name         string
+		input        string
+		emptyNewline bool
+
+		want string
+	}{
+		{
+			name: "empty string",
+		},
+		{
+			name:         `empty string with empty newline`,
+			emptyNewline: true,
+
+			want: "\n",
+		},
+		{
+			name:  "simple attribute",
+			input: `value => 3.1415`,
+
+			want: `
+  value => 3.1415
+`,
+		},
+		{
+			name: "simple attribute with newline",
+			input: `value => 3.1415
+`,
+
+			want: `
+  value => 3.1415
+`,
+		},
+		{
+			name: "simple attribute with comment",
+			input: `// comment
+value => 3.1415`,
+
+			want: `
+  // comment
+  value => 3.1415
+`,
+		},
+		{
+			name: "block",
+			input: `add_field {
+  // comment
+  value => 3.1415
+}
+
+add_tag => [ "foobar" ]
+`,
+
+			want: `
+  add_field {
+    // comment
+    value => 3.1415
+  }
+
+  add_tag => [ "foobar" ]
+`,
+		},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			got := prefix(tc.input, tc.emptyNewline)
+
+			if tc.want != got {
+				t.Errorf("want %q, got %q", tc.want, got)
+			}
+		})
+	}
+}