diff --git a/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/InMemorySwapStore.java b/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/InMemorySwapStore.java
new file mode 100644
index 0000000000..05a919bb26
--- /dev/null
+++ b/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/InMemorySwapStore.java
@@ -0,0 +1,50 @@
+package uk.ac.ic.wlgitbridge.bridge.swap;
+
+import org.apache.commons.io.IOUtils;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Created by winston on 23/08/2016.
+ */
+public class InMemorySwapStore implements SwapStore {
+
+    private final Map<String, byte[]> store;
+
+    public InMemorySwapStore() {
+        store = new HashMap<>();
+    }
+
+    @Override
+    public void upload(
+            String projectName,
+            InputStream uploadStream,
+            long contentLength
+    ) throws IOException {
+        store.put(
+                projectName,
+                IOUtils.toByteArray(uploadStream, contentLength)
+        );
+    }
+
+    @Override
+    public InputStream openDownloadStream(String projectName) {
+        byte[] buf = store.get(projectName);
+        if (buf == null) {
+            throw new IllegalArgumentException(
+                    "no such project in swap store: " + projectName
+            );
+        }
+        return new ByteArrayInputStream(buf);
+    }
+
+    @Override
+    public void remove(String projectName) {
+        store.remove(projectName);
+    }
+
+}
diff --git a/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/SwapJobImpl.java b/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/SwapJobImpl.java
index 06209df6d7..26f27891b0 100644
--- a/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/SwapJobImpl.java
+++ b/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/SwapJobImpl.java
@@ -3,6 +3,7 @@ package uk.ac.ic.wlgitbridge.bridge.swap;
 import uk.ac.ic.wlgitbridge.bridge.db.DBStore;
 import uk.ac.ic.wlgitbridge.bridge.lock.ProjectLock;
 import uk.ac.ic.wlgitbridge.bridge.repo.RepoStore;
+import uk.ac.ic.wlgitbridge.util.Log;
 
 import java.time.Duration;
 import java.util.Timer;
@@ -52,7 +53,8 @@ public class SwapJobImpl implements SwapJob {
     }
 
     private void doSwap() {
-        swaps.incrementAndGet();
+        Log.info("Running {}th swap", swaps.getAndIncrement());
+
     }
 
 }
diff --git a/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/SwapStore.java b/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/SwapStore.java
index 4394adca11..dc82c35706 100644
--- a/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/SwapStore.java
+++ b/services/git-bridge/src/main/java/uk/ac/ic/wlgitbridge/bridge/swap/SwapStore.java
@@ -1,5 +1,6 @@
 package uk.ac.ic.wlgitbridge.bridge.swap;
 
+import java.io.IOException;
 import java.io.InputStream;
 
 /**
@@ -7,7 +8,11 @@ import java.io.InputStream;
  */
 public interface SwapStore {
 
-    void upload(String projectName, InputStream uploadStream, long contentLength);
+    void upload(
+            String projectName,
+            InputStream uploadStream,
+            long contentLength
+    ) throws IOException;
 
     InputStream openDownloadStream(String projectName);
 
diff --git a/services/git-bridge/src/test/java/uk/ac/ic/wlgitbridge/bridge/swap/InMemorySwapStoreTest.java b/services/git-bridge/src/test/java/uk/ac/ic/wlgitbridge/bridge/swap/InMemorySwapStoreTest.java
new file mode 100644
index 0000000000..34553ae287
--- /dev/null
+++ b/services/git-bridge/src/test/java/uk/ac/ic/wlgitbridge/bridge/swap/InMemorySwapStoreTest.java
@@ -0,0 +1,94 @@
+package uk.ac.ic.wlgitbridge.bridge.swap;
+
+import org.apache.commons.io.IOUtils;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+
+import static org.junit.Assert.assertArrayEquals;
+
+/**
+ * Created by winston on 23/08/2016.
+ */
+public class InMemorySwapStoreTest {
+
+    private final InMemorySwapStore swapStore = new InMemorySwapStore();
+
+    @Rule
+    public final ExpectedException exception = ExpectedException.none();
+
+    @Test
+    public void downloadingNonExistentFileThrows() {
+        exception.expect(IllegalArgumentException.class);
+        swapStore.openDownloadStream("asdf");
+    }
+
+    @Test
+    public void canDownloadUploadedFiles() throws IOException {
+        byte[] proj1Contents = "helloproj1".getBytes();
+        byte[] proj2Contents = "asdfproj2".getBytes();
+        swapStore.upload(
+                "proj1",
+                new ByteArrayInputStream(proj1Contents),
+                proj1Contents.length
+        );
+        swapStore.upload(
+                "proj2",
+                new ByteArrayInputStream(proj2Contents),
+                proj2Contents.length
+        );
+        assertArrayEquals(
+                proj1Contents,
+                IOUtils.toByteArray(swapStore.openDownloadStream("proj1"))
+        );
+        assertArrayEquals(
+                proj2Contents,
+                IOUtils.toByteArray(swapStore.openDownloadStream("proj2"))
+        );
+    }
+
+    @Test
+    public void uploadingForTheSameProjectOverwritesTheFile() throws IOException {
+        byte[] proj1Contents = "helloproj1".getBytes();
+        byte[] proj1NewContents = "goodbyeproj1".getBytes();
+        swapStore.upload(
+                "proj1",
+                new ByteArrayInputStream(proj1Contents),
+                proj1Contents.length
+        );
+        assertArrayEquals(
+                proj1Contents,
+                IOUtils.toByteArray(swapStore.openDownloadStream("proj1"))
+        );
+        swapStore.upload(
+                "proj1",
+                new ByteArrayInputStream(proj1NewContents),
+                proj1NewContents.length
+        );
+        assertArrayEquals(
+                proj1NewContents,
+                IOUtils.toByteArray(swapStore.openDownloadStream("proj1"))
+        );
+    }
+
+    @Test
+    public void canRemoveFiles() throws IOException {
+        byte[] projContents = "total garbage".getBytes();
+        swapStore.upload(
+                "proj",
+                new ByteArrayInputStream(projContents),
+                projContents.length
+        );
+        assertArrayEquals(
+                projContents,
+                IOUtils.toByteArray(swapStore.openDownloadStream("proj"))
+        );
+        swapStore.remove("proj");
+        exception.expect(IllegalArgumentException.class);
+        swapStore.openDownloadStream("proj");
+    }
+
+}
\ No newline at end of file