diff --git a/acme4j-letsencrypt/pom.xml b/acme4j-letsencrypt/pom.xml
index 06798524..68388396 100644
--- a/acme4j-letsencrypt/pom.xml
+++ b/acme4j-letsencrypt/pom.xml
@@ -28,6 +28,21 @@
     <name>acme4j Let's Encrypt</name>
     <description>Let's Encrypt service provider for acme4j</description>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>2.19</version>
+                <configuration>
+                    <parallel>classes</parallel>
+                    <threadCount>10</threadCount>
+                    <excludedGroups>org.shredzone.acme4j.provider.LetsEncryptAcmeClientProviderTest$RequiresNetwork</excludedGroups>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
     <dependencies>
         <dependency>
             <groupId>org.shredzone.acme4j</groupId>
diff --git a/acme4j-letsencrypt/src/main/java/org/shredzone/acme4j/provider/LetsEncryptAcmeClientProvider.java b/acme4j-letsencrypt/src/main/java/org/shredzone/acme4j/provider/LetsEncryptAcmeClientProvider.java
index 1830fda4..cf62cd37 100644
--- a/acme4j-letsencrypt/src/main/java/org/shredzone/acme4j/provider/LetsEncryptAcmeClientProvider.java
+++ b/acme4j-letsencrypt/src/main/java/org/shredzone/acme4j/provider/LetsEncryptAcmeClientProvider.java
@@ -92,7 +92,7 @@ public class LetsEncryptAcmeClientProvider extends AbstractAcmeClientProvider {
      * Lazily creates an {@link SSLSocketFactory} that exclusively accepts the Let's
      * Encrypt certificate.
      */
-    private SSLSocketFactory createSocketFactory() throws IOException {
+    protected SSLSocketFactory createSocketFactory() throws IOException {
         if (sslSocketFactory == null) {
             try {
                 KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
diff --git a/acme4j-letsencrypt/src/test/java/org/shredzone/acme4j/provider/LetsEncryptAcmeClientProviderTest.java b/acme4j-letsencrypt/src/test/java/org/shredzone/acme4j/provider/LetsEncryptAcmeClientProviderTest.java
new file mode 100644
index 00000000..5776e5dc
--- /dev/null
+++ b/acme4j-letsencrypt/src/test/java/org/shredzone/acme4j/provider/LetsEncryptAcmeClientProviderTest.java
@@ -0,0 +1,99 @@
+/*
+ * acme4j - Java ACME client
+ *
+ * Copyright (C) 2015 Richard "Shred" Körber
+ *   http://acme4j.shredzone.org
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ */
+package org.shredzone.acme4j.provider;
+
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import javax.net.ssl.HttpsURLConnection;
+import javax.net.ssl.SSLHandshakeException;
+import javax.net.ssl.SSLSocketFactory;
+
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+/**
+ * Unit tests for {@link LetsEncryptAcmeClientProvider}.
+ *
+ * @author Richard "Shred" Körber
+ */
+public class LetsEncryptAcmeClientProviderTest {
+
+    public interface RequiresNetwork {}
+
+    /**
+     * Tests if the provider accepts the correct URIs.
+     */
+    @Test
+    public void testAccepts() throws URISyntaxException {
+        LetsEncryptAcmeClientProvider provider = new LetsEncryptAcmeClientProvider();
+
+        assertThat(provider.accepts(new URI("acme://letsencrypt.org")), is(true));
+        assertThat(provider.accepts(new URI("acme://letsencrypt.org/")), is(true));
+        assertThat(provider.accepts(new URI("acme://letsencrypt.org/staging")), is(true));
+        assertThat(provider.accepts(new URI("acme://letsencrypt.org/v01")), is(true));
+        assertThat(provider.accepts(new URI("acme://example.com")), is(false));
+        assertThat(provider.accepts(new URI("http://example.com/acme")), is(false));
+        assertThat(provider.accepts(new URI("https://example.com/acme")), is(false));
+    }
+
+    /**
+     * Test if the {@link LetsEncryptAcmeClientProvider#openConnection(URI)} accepts only
+     * the Let's Encrypt certificate.
+     */
+    @Test
+    @Category(RequiresNetwork.class)
+    public void testCertificate() throws IOException, URISyntaxException {
+        LetsEncryptAcmeClientProvider provider = new LetsEncryptAcmeClientProvider();
+
+        try {
+            HttpURLConnection goodConn = provider.openConnection(
+                            new URI("https://acme-staging.api.letsencrypt.org/directory"));
+            assertThat(goodConn, is(instanceOf(HttpsURLConnection.class)));
+            goodConn.connect();
+        } catch (SSLHandshakeException ex) {
+            fail("Connection does not accept Let's Encrypt certificate");
+        }
+
+        try {
+            HttpURLConnection badConn = provider.openConnection(
+                            new URI("https://www.google.com"));
+            assertThat(badConn, is(instanceOf(HttpsURLConnection.class)));
+            badConn.connect();
+            fail("Connection accepts foreign certificate");
+        } catch (SSLHandshakeException ex) {
+            // expected
+        }
+    }
+
+    /**
+     * Test that the {@link SSLSocketFactory} can be instantiated and is cached.
+     */
+    @Test
+    public void testCreateSocketFactory() throws IOException {
+        LetsEncryptAcmeClientProvider provider = new LetsEncryptAcmeClientProvider();
+
+        SSLSocketFactory factory1 = provider.createSocketFactory();
+        assertThat(factory1, is(notNullValue()));
+
+        SSLSocketFactory factory2 = provider.createSocketFactory();
+        assertThat(factory1, is(sameInstance(factory2)));
+    }
+
+}
diff --git a/pom.xml b/pom.xml
index 0220510c..6dacdf60 100644
--- a/pom.xml
+++ b/pom.xml
@@ -128,7 +128,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-surefire-report-plugin</artifactId>
-                <version>2.17</version>
+                <version>2.19</version>
             </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
@@ -149,7 +149,7 @@
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
-            <version>[4,)</version>
+            <version>[4.7,)</version>
             <scope>test</scope>
         </dependency>
         <dependency>