diff --git a/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/io/http/ning/NingHttpHeaders.java b/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/io/http/ning/NingHttpHeaders.java
new file mode 100644
index 0000000000..69093f37c4
--- /dev/null
+++ b/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/io/http/ning/NingHttpHeaders.java
@@ -0,0 +1,46 @@
+package uk.ac.ic.wlgitbridge.io.http.ning;
+
+import com.ning.http.client.FluentCaseInsensitiveStringsMap;
+import com.ning.http.client.HttpResponseHeaders;
+
+import java.util.*;
+
+public class NingHttpHeaders extends HttpResponseHeaders {
+
+    private final FluentCaseInsensitiveStringsMap map;
+
+    private NingHttpHeaders(FluentCaseInsensitiveStringsMap map) {
+        this.map = map;
+    }
+
+    public static NingHttpHeadersBuilder builder() {
+        return new NingHttpHeadersBuilder();
+    }
+
+    @Override
+    public FluentCaseInsensitiveStringsMap getHeaders() {
+        return map;
+    }
+
+    public static class NingHttpHeadersBuilder {
+
+        private final Map<String, Collection<String>> map;
+
+        private NingHttpHeadersBuilder() {
+            map = new HashMap<>();
+        }
+
+        public NingHttpHeadersBuilder addHeader(String key, String... values) {
+            map.computeIfAbsent(key, __ -> new ArrayList<>())
+                    .addAll(Arrays.asList(values));
+            return this;
+        }
+
+        public NingHttpHeaders build() {
+            return new NingHttpHeaders(
+                    new FluentCaseInsensitiveStringsMap(map));
+        }
+
+    }
+
+}
diff --git a/services/git-bridge/src/test/java/uk/ac/ic/wlgitbridge/bridge/resource/UrlResourceCacheTest.java b/services/git-bridge/src/test/java/uk/ac/ic/wlgitbridge/bridge/resource/UrlResourceCacheTest.java
index e180a07731..77c38f8996 100644
--- a/services/git-bridge/src/test/java/uk/ac/ic/wlgitbridge/bridge/resource/UrlResourceCacheTest.java
+++ b/services/git-bridge/src/test/java/uk/ac/ic/wlgitbridge/bridge/resource/UrlResourceCacheTest.java
@@ -1,13 +1,19 @@
 package uk.ac.ic.wlgitbridge.bridge.resource;
 
+import com.ning.http.client.HttpResponseHeaders;
 import org.junit.Test;
 import uk.ac.ic.wlgitbridge.bridge.db.noop.NoopDbStore;
+import uk.ac.ic.wlgitbridge.git.exception.SizeLimitExceededException;
 import uk.ac.ic.wlgitbridge.io.http.ning.NingHttpClientFacade;
+import uk.ac.ic.wlgitbridge.io.http.ning.NingHttpHeaders;
+import uk.ac.ic.wlgitbridge.util.FunctionT;
 
-import java.util.Collections;
+import java.util.HashMap;
 import java.util.Optional;
 
+import static org.mockito.Matchers.any;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class UrlResourceCacheTest {
 
@@ -22,6 +28,13 @@ public class UrlResourceCacheTest {
     private final UrlResourceCache cache
             = new UrlResourceCache(new NoopDbStore(), http);
 
+    private static HttpResponseHeaders withContentLength(long cl) {
+        return NingHttpHeaders
+                .builder()
+                .addHeader("Content-Length", String.valueOf(cl))
+                .build();
+    }
+
     @Test
     public void getThrowsSizeLimitWhenContentLengthTooBig() throws Exception {
         when(http.get(any(), any())).thenAnswer(invoc -> {
@@ -35,7 +48,7 @@ public class UrlResourceCacheTest {
 
         cache.get(
                 PROJ, URL, NEW_PATH,
-                Collections.emptyMap(), Collections.emptyMap(),
+                new HashMap<>(), new HashMap<>(),
                 Optional.of(2L)
         );
     }