Replace %q to %d for invalid code string formatting

Author: purnesh42H

.vscode/launch.json

@@ -0,0 +1,15 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Launch Package",
+            "type": "go",
+            "request": "launch",
+            "mode": "auto",
+            "program": "${fileDirname}"
+        }
+    ]
+}

codes/codes.go

@@ -235,7 +235,7 @@ func (c *Code) UnmarshalJSON(b []byte) error {
 
 	if ci, err := strconv.ParseUint(string(b), 10, 32); err == nil {
 		if ci >= _maxCode {
-			return fmt.Errorf("invalid code: %q", ci)
+			return fmt.Errorf("invalid code: %d", ci)
 		}
 
 		*c = Code(ci)

codes/codes_test.go

@@ -91,3 +91,12 @@ func (s) TestUnmarshalJSON_MarshalUnmarshal(t *testing.T) {
 		}
 	}
 }
+
+func (s) TestUnmarshalJSON_InvalidIntegerCode(t *testing.T) {
+	var got Code
+	wantErr := "invalid code: 200"
+	err := got.UnmarshalJSON([]byte("200"))
+	if err.Error() != wantErr { // for integer invalid code, expect integer value in error message
+		t.Errorf("got.UnmarshalJSON(200) != %s; got=%s", wantErr, err.Error())
+	}
+}