1 files changed, 82 insertions, 0 deletions
diff --git a/packages/web-util/src/tests/swr.ts b/packages/web-util/src/tests/swr.ts
new file mode 100644
index 000000000..95c62ebea
--- /dev/null
+++ b/packages/web-util/src/tests/swr.ts
@@ -0,0 +1,82 @@
+/*
+ This file is part of GNU Taler
+ (C) 2021 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+import { ComponentChildren, FunctionalComponent, h, VNode } from "preact";
+import { MockEnvironment, Query } from "./mock.js";
+import { SWRConfig } from "swr";
+
+export { Query };
+/**
+ * Helper for hook that use SWR inside.
+ * 
+ * buildTestingContext() will return a testing context
+ * 
+ */
+export class SwrMockEnvironment extends MockEnvironment {
+  constructor(debug = false) {
+    super(debug);
+  }
+
+  mockApiIfNeeded(): void {
+    null; // do nothing
+  }
+
+  public buildTestingContext(): FunctionalComponent<{
+    children: ComponentChildren;
+  }> {
+    const __REGISTER_REQUEST = this.registerRequest.bind(this);
+    return function TestingContext({
+      children,
+    }: {
+      children: ComponentChildren;
+    }): VNode {
+      return h(
+        SWRConfig,
+        {
+          value: {
+            fetcher: (url: string, options: object) => {
+              const mocked = __REGISTER_REQUEST(
+                {
+                  method: "get",
+                  url,
+                },
+                {},
+              );
+              if (!mocked) return undefined;
+              if (mocked.status > 400) {
+                const e: any = Error("simulated error for testing");
+                //example error handling from https://swr.vercel.app/docs/error-handling
+                e.status = mocked.status;
+                throw e;
+              }
+              return mocked.payload;
+            },
+            //These options are set for ending the test faster
+            //otherwise SWR will create timeouts that will live after the test finished
+            loadingTimeout: 0,
+            dedupingInterval: 0,
+            shouldRetryOnError: false,
+            errorRetryInterval: 0,
+            errorRetryCount: 0,
+            //clean cache for every test
+            provider: () => new Map(),
+          },
+        },
+        children,
+      );
+    };
+  }
+}