t_common_test.go: added function fileExists()

t_common_test.go

@@ -6,6 +6,7 @@ package expr
 
 import (
 	"errors"
+	"os"
 	"path"
 	"runtime"
 	"strings"
@@ -176,3 +177,10 @@ func testIteratorCallOp(t *testing.T, section string, it kern.Iterator) {
 		t.Errorf(`%s -- CallOperation("fake") should return error`, section)
 	}
 }
+
+// Test utilities
+
+func fileExists(filePath string) bool {
+	_, err := os.Stat(filePath)
+	return !errors.Is(err, os.ErrNotExist)
+}