test: add tests for errors

errors_test.go

@@ -0,0 +1,22 @@
+// Copyright © 2020 Mike Berezin
+//
+// Use of this source code is governed by an MIT license.
+// Details in the LICENSE file.
+
+package airtable
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestHTTPClientError_Error(t *testing.T) {
+	e := &HTTPClientError{
+		StatusCode: 300,
+		Err:        errors.New("error message"),
+	}
+	expected := "status 300, err: error message"
+	if got := e.Error(); got != expected {
+		t.Errorf("HTTPClientError.Error() = %v, want %v", got, expected)
+	}
+}