api: Add ApiConnection.patch

The tests, ApiConnection.{post,patch,delete}, are mostly similar to
each other, because the majority of them are testing that the params
are parsed into the body with the same content type.

If we find the need to update these test cases with new examples, it
will be ripe to refactor them with a helper. Until then, just duplicate
them for simplicity.

Signed-off-by: Zixuan James Li <zixuan@zulip.com>

Author: PIG208

lib/api/core.dart

@@ -224,6 +224,16 @@ class ApiConnection {
     return send(routeName, fromJson, request);
   }
 
+  Future<T> patch<T>(String routeName, T Function(Map<String, dynamic>) fromJson,
+      String path, Map<String, dynamic>? params) async {
+    final url = realmUrl.replace(path: "/api/v1/$path");
+    final request = http.Request('PATCH', url);
+    if (params != null) {
+      request.bodyFields = encodeParameters(params)!;
+    }
+    return send(routeName, fromJson, request);
+  }
+
   Future<T> delete<T>(String routeName, T Function(Map<String, dynamic>) fromJson,
       String path, Map<String, dynamic>? params) async {
     final url = realmUrl.replace(path: "/api/v1/$path");

test/api/core_test.dart

@@ -201,6 +201,37 @@ void main() {
     checkRequest(['asdf'.codeUnits], 100, filename: null);
   });
 
+  test('ApiConnection.patch', () async {
+    void checkRequest(Map<String, dynamic>? params, String expectedBody, {bool expectContentType = true}) {
+      finish(FakeApiConnection.with_(account: eg.selfAccount, (connection) async {
+        connection.prepare(json: {});
+        await connection.patch(kExampleRouteName, (json) => json, 'example/route', params);
+        check(connection.lastRequest!).isA<http.Request>()
+          ..method.equals('PATCH')
+          ..url.asString.equals('${eg.realmUrl.origin}/api/v1/example/route')
+          ..headers.deepEquals({
+            ...authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey),
+            ...kFallbackUserAgentHeader,
+            if (expectContentType)
+              'content-type': 'application/x-www-form-urlencoded; charset=utf-8',
+          })
+          ..body.equals(expectedBody);
+      }));
+    }
+
+    checkRequest(null,                                   '', expectContentType: false);
+    checkRequest({},                                     '');
+    checkRequest({'x': 3},                               'x=3');
+    checkRequest({'x': 3, 'y': 4},                       'x=3&y=4');
+    checkRequest({'x': null},                            'x=null');
+    checkRequest({'x': true},                            'x=true');
+    checkRequest({'x': 'foo'},                           'x=%22foo%22');
+    checkRequest({'x': [1, 2]},                          'x=%5B1%2C2%5D');
+    checkRequest({'x': {'y': 1}},                        'x=%7B%22y%22%3A1%7D');
+    checkRequest({'x': RawParameter('foo')},             'x=foo');
+    checkRequest({'x': RawParameter('foo'), 'y': 'bar'}, 'x=foo&y=%22bar%22');
+  });
+
   test('ApiConnection.delete', () async {
     void checkRequest(Map<String, dynamic>? params, String expectedBody, {bool expectContentType = true}) {
       finish(FakeApiConnection.with_(account: eg.selfAccount, (connection) async {