Add metric for content-length header distribution

service/src/test/java/org/whispersystems/textsecuregcm/filters/ContentLengthFilterTest.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2021 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.filters;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import javax.ws.rs.container.ContainerRequestContext;
+import org.junit.jupiter.api.Test;
+import org.whispersystems.textsecuregcm.metrics.TrafficSource;
+
+class ContentLengthFilterTest {
+
+  @Test
+  void testFilter() throws Exception {
+
+    final ContentLengthFilter contentLengthFilter = new ContentLengthFilter(TrafficSource.WEBSOCKET);
+
+    final ContainerRequestContext requestContext = mock(ContainerRequestContext.class);
+
+    when(requestContext.getLength()).thenReturn(-1);
+    when(requestContext.getLength()).thenReturn(Integer.MAX_VALUE);
+    when(requestContext.getLength()).thenThrow(RuntimeException.class);
+
+    contentLengthFilter.filter(requestContext);
+    contentLengthFilter.filter(requestContext);
+    contentLengthFilter.filter(requestContext);
+  }
+}