feat(code_push_client): add getUsage (#678)

packages/shorebird_code_push_client/lib/src/code_push_client.dart

@@ -445,6 +445,20 @@ class CodePushClient {
     return decoded.artifacts;
   }
 
+  /// Get all usage information for the associated account.
+  Future<List<AppUsage>> getUsage() async {
+    final response = await _httpClient.get(Uri.parse('$_v1/usage'));
+
+    if (response.statusCode != HttpStatus.ok) {
+      throw _parseErrorResponse(response.statusCode, response.body);
+    }
+
+    final decoded = GetUsageResponse.fromJson(
+      json.decode(response.body) as Map<String, dynamic>,
+    );
+    return decoded.apps;
+  }
+
   /// Promote the [patchId] to the [channelId].
   Future<void> promotePatch({
     required int patchId,

packages/shorebird_code_push_client/test/src/code_push_client_test.dart

@@ -1860,6 +1860,81 @@ void main() {
       });
     });
 
+    group('getUsage', () {
+      test('makes the correct request', () async {
+        codePushClient.getUsage().ignore();
+        final request = verify(() => httpClient.send(captureAny()))
+            .captured
+            .single as http.BaseRequest;
+        expect(request.method, equals('GET'));
+        expect(request.url, equals(v1('usage')));
+        expect(request.hasStandardHeaders, isTrue);
+      });
+
+      test('throws an exception if the http request fails (unknown)', () async {
+        when(() => httpClient.send(any())).thenAnswer(
+          (_) async => http.StreamedResponse(
+            const Stream.empty(),
+            HttpStatus.failedDependency,
+          ),
+        );
+
+        expect(
+          codePushClient.getUsage(),
+          throwsA(
+            isA<CodePushException>().having(
+              (e) => e.message,
+              'message',
+              CodePushClient.unknownErrorMessage,
+            ),
+          ),
+        );
+      });
+
+      test('throws an exception if the http request fails', () async {
+        when(() => httpClient.send(any())).thenAnswer(
+          (_) async => http.StreamedResponse(
+            Stream.value(utf8.encode(json.encode(errorResponse.toJson()))),
+            HttpStatus.failedDependency,
+          ),
+        );
+
+        expect(
+          codePushClient.getUsage(),
+          throwsA(
+            isA<CodePushException>().having(
+              (e) => e.message,
+              'message',
+              errorResponse.message,
+            ),
+          ),
+        );
+      });
+
+      test('completes when request succeeds', () async {
+        final expected = [
+          AppUsage(
+            id: 'test-app-id',
+            platforms: [],
+          )
+        ];
+
+        when(() => httpClient.send(any())).thenAnswer(
+          (_) async => http.StreamedResponse(
+            Stream.value(
+              utf8.encode(
+                json.encode(GetUsageResponse(apps: expected)),
+              ),
+            ),
+            HttpStatus.ok,
+          ),
+        );
+
+        final actual = await codePushClient.getUsage();
+        expect(json.encode(actual), equals(json.encode(expected)));
+      });
+    });
+
     group('promotePatch', () {
       const patchId = 0;
       const channelId = 0;