diff --git a/k9mail-library/src/main/java/com/fsck/k9/mail/store/imap/ImapConnection.java b/k9mail-library/src/main/java/com/fsck/k9/mail/store/imap/ImapConnection.java
index 88482c4b6..cd679a5f8 100644
--- a/k9mail-library/src/main/java/com/fsck/k9/mail/store/imap/ImapConnection.java
+++ b/k9mail-library/src/main/java/com/fsck/k9/mail/store/imap/ImapConnection.java
@@ -601,10 +601,18 @@ class ImapConnection {
     }
 
     private List<ImapResponse> receiveCapabilities(List<ImapResponse> responses) {
-        capabilities = ImapResponseParser.parseCapabilities(responses);
+        Set<String> receivedCapabilities = ImapResponseParser.parseCapabilities(responses);
+        /* RFC 3501 6.2.3
+            A server MAY include a CAPABILITY response code in the tagged OK
+            response to a successful LOGIN command in order to send
+            capabilities automatically.  It is unnecessary for a client to
+            send a separate CAPABILITY command if it recognizes these
+            automatic capabilities.
+        */
         if (K9MailLib.isDebug()) {
-            Log.d(LOG_TAG, "Saving " + capabilities + " capabilities for " + getLogId());
+            Log.d(LOG_TAG, "Saving " + receivedCapabilities + " capabilities for " + getLogId());
         }
+        capabilities.addAll(receivedCapabilities);
         return responses;
     }
 }
diff --git a/k9mail/build.gradle b/k9mail/build.gradle
index c99ed2f0c..bc8198a57 100644
--- a/k9mail/build.gradle
+++ b/k9mail/build.gradle
@@ -5,6 +5,9 @@ apply from: '../gradle/plugins/findbugs-android.gradle'
 
 repositories {
     jcenter()
+    maven {
+        url "https://oss.sonatype.org/content/repositories/snapshots/"
+    }
 }
 
 dependencies {
@@ -21,9 +24,10 @@ dependencies {
     androidTestCompile 'com.android.support.test:testing-support-lib:0.1'
     androidTestCompile 'com.android.support.test.espresso:espresso-core:2.0'
 
-    androidTestCompile("com.icegreen:greenmail:1.3.1b") {
+    androidTestCompile("com.icegreen:greenmail:1.4.1-SNAPSHOT") {
         // Use a better, later version
-        exclude group: "javax.mail"
+        exclude group: "com.sun.mail"
+        exclude group: "junit"
     }
 
     // this version avoids some "Ignoring InnerClasses attribute for an anonymous inner class" warnings
diff --git a/k9mail/src/androidTest/java/com/fsck/k9/endtoend/framework/StubMailServer.java b/k9mail/src/androidTest/java/com/fsck/k9/endtoend/framework/StubMailServer.java
index d8d1df2a3..c7d5b97ec 100644
--- a/k9mail/src/androidTest/java/com/fsck/k9/endtoend/framework/StubMailServer.java
+++ b/k9mail/src/androidTest/java/com/fsck/k9/endtoend/framework/StubMailServer.java
@@ -37,5 +37,9 @@ public class StubMailServer {
     public int getImapPort() {
         return IMAP_SERVER_SETUP.getPort();
     }
+
+    public void stop() {
+        greenmail.stop();
+    }
 }
 
diff --git a/k9mail/src/androidTest/java/com/fsck/k9/mail/store/imap/ImapConnectionTest.java b/k9mail/src/androidTest/java/com/fsck/k9/mail/store/imap/ImapConnectionTest.java
new file mode 100644
index 000000000..75074195e
--- /dev/null
+++ b/k9mail/src/androidTest/java/com/fsck/k9/mail/store/imap/ImapConnectionTest.java
@@ -0,0 +1,160 @@
+package com.fsck.k9.mail.store.imap;
+
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import com.fsck.k9.endtoend.framework.StubMailServer;
+import com.fsck.k9.endtoend.framework.UserForImap;
+import com.fsck.k9.mail.AuthType;
+import com.fsck.k9.mail.AuthenticationFailedException;
+import com.fsck.k9.mail.ConnectionSecurity;
+import junit.framework.TestCase;
+
+import static org.junit.Assert.assertArrayEquals;
+
+
+public class ImapConnectionTest extends TestCase {
+    private StubMailServer stubMailServer;
+    private ImapConnection connection;
+    private TestImapSettings settings = new TestImapSettings(UserForImap.TEST_USER);
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        stubMailServer = new StubMailServer();
+        connection = new ImapConnection(settings, null,
+                null);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        stubMailServer.stop();
+    }
+
+    public void testOpenConnectionWithWrongCredentials() throws Exception {
+        connection = new ImapConnection(new TestImapSettings("wrong", "password"), null, null);
+        try {
+            connection.open();
+            fail("expected exception");
+        } catch (AuthenticationFailedException e) {
+            assertTrue(e.getMessage().contains("Invalid login/password"));
+            assertFalse(connection.isOpen());
+        }
+    }
+
+    public void testOpenConnection() throws Exception {
+        connection.open();
+        assertTrue(connection.isOpen());
+    }
+
+    public void testOpenAndCloseConnection() throws Exception {
+        connection.open();
+        connection.close();
+        assertFalse(connection.isOpen());
+    }
+
+    public void testCapabilities() throws Exception {
+        connection.open();
+        List<String> capabilities = new ArrayList<String>(connection.getCapabilities());
+        Collections.sort(capabilities);
+        assertArrayEquals(new String[] { "IMAP4REV1", "LITERAL+", "QUOTA" }, capabilities.toArray());
+    }
+
+    public void testPathPrefixGetsSetCorrectly() throws Exception {
+        connection.open();
+        assertEquals("", settings.getPathPrefix());
+    }
+
+    public void testPathDelimiterGetsParsedCorrectly() throws Exception {
+        connection.open();
+        assertEquals(".", settings.getPathDelimiter());
+    }
+
+    private class TestImapSettings implements ImapSettings {
+        private String pathPrefix;
+        private String pathDelimiter;
+        private String username;
+        private String password;
+
+        public TestImapSettings(UserForImap userForImap) {
+            this(userForImap.loginUsername, userForImap.password);
+        }
+
+        public TestImapSettings(String username, String password) {
+            this.username = username;
+            this.password = password;
+        }
+
+        @Override
+        public String getHost() {
+            return stubMailServer.getImapBindAddress();
+        }
+
+        @Override
+        public int getPort() {
+            return stubMailServer.getImapPort();
+        }
+
+        @Override
+        public ConnectionSecurity getConnectionSecurity() {
+            return ConnectionSecurity.NONE;
+        }
+
+        @Override
+        public AuthType getAuthType() {
+            return AuthType.PLAIN;
+        }
+
+        @Override
+        public String getUsername() {
+            return username;
+        }
+
+        @Override
+        public String getPassword() {
+            return password;
+        }
+
+        @Override
+        public String getClientCertificateAlias() {
+            return null;
+        }
+
+        @Override
+        public boolean useCompression(int type) {
+            return false;
+        }
+
+        @Override
+        public String getPathPrefix() {
+            return pathPrefix;
+        }
+
+        @Override
+        public void setPathPrefix(String prefix) {
+            pathPrefix = prefix;
+        }
+
+        @Override
+        public String getPathDelimiter() {
+            return pathDelimiter;
+        }
+
+        @Override
+        public void setPathDelimiter(String delimiter) {
+            pathDelimiter = delimiter;
+        }
+
+        @Override
+        public String getCombinedPrefix() {
+            return null;
+        }
+
+        @Override
+        public void setCombinedPrefix(String prefix) {
+        }
+    }
+}