diff --git a/src/com/google/enterprise/adaptor/opentext/ValidatedUri.java b/src/com/google/enterprise/adaptor/opentext/ValidatedUri.java
index bf3c3ed..8119bf0 100644
--- a/src/com/google/enterprise/adaptor/opentext/ValidatedUri.java
+++ b/src/com/google/enterprise/adaptor/opentext/ValidatedUri.java
@@ -53,7 +53,7 @@ public ValidatedUri(String uriString) throws URISyntaxException {
     }
     try {
       // Basic syntax checking, with more understandable error messages.
-      // Also ensures the URI is a URL, not a URN.
+      // Also ensures the URI is a URL, not a URN, and is absolute.
       new URL(uriString);
       // Advanced syntax checking, with more cryptic error messages.
       uri = new URI(uriString);
@@ -65,10 +65,6 @@ public ValidatedUri(String uriString) throws URISyntaxException {
       throw new URISyntaxException(uriString, reason);
     }
 
-    if (!uri.isAbsolute()) {
-      throw new URISyntaxException(uriString, "relative URIs are not allowed");
-    }
-
     if (Strings.isNullOrEmpty(uri.getHost())) {
       throw new URISyntaxException(uriString, "no host");
     }
diff --git a/test/com/google/enterprise/adaptor/opentext/Logging.java b/test/com/google/enterprise/adaptor/opentext/Logging.java
new file mode 100644
index 0000000..9846faa
--- /dev/null
+++ b/test/com/google/enterprise/adaptor/opentext/Logging.java
@@ -0,0 +1,53 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.enterprise.adaptor.opentext;
+
+import java.util.Collection;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.LogRecord;
+import java.util.logging.Logger;
+
+/** Tools to test logging output. */
+public class Logging {
+  /**
+   * Enables logging and captures matching log messages. The messages
+   * will not be localized or formatted.
+   *
+   * @param clazz the class to enable logging for
+   * @param substring capture log messages containing this substring
+   * @param output captured messages will be added to this collection
+   */
+  public static void captureLogMessages(Class<?> clazz,
+      final String substring, final Collection<? super String> output) {
+    Logger logger = Logger.getLogger(clazz.getName());
+    logger.setLevel(Level.ALL);
+
+    logger.addHandler(new Handler() {
+        @Override public void close() {}
+        @Override public void flush() {}
+
+        @Override public void publish(LogRecord record) {
+          if (record.getMessage().contains(substring)) {
+            output.add(record.getMessage());
+          }
+        }
+      });
+  }
+
+  private Logging() {
+    throw new AssertionError();
+  }
+}
diff --git a/test/com/google/enterprise/adaptor/opentext/ValidatedUriTest.java b/test/com/google/enterprise/adaptor/opentext/ValidatedUriTest.java
index cdca8fe..7ae9a56 100644
--- a/test/com/google/enterprise/adaptor/opentext/ValidatedUriTest.java
+++ b/test/com/google/enterprise/adaptor/opentext/ValidatedUriTest.java
@@ -14,17 +14,13 @@
 
 package com.google.enterprise.adaptor.opentext;
 
+import static com.google.enterprise.adaptor.opentext.Logging.captureLogMessages;
 import static org.junit.Assert.assertEquals;
 
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.List;
-import java.util.logging.Handler;
-import java.util.logging.Level;
-import java.util.logging.LogRecord;
-import java.util.logging.Logger;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
@@ -50,9 +46,17 @@ public void testEmptyUrl() throws Exception {
   @Test
   public void testNoProtocol() throws Exception {
     thrown.expect(URISyntaxException.class);
+    thrown.expectMessage("no protocol");
     new ValidatedUri("//foo/bar");
   }
 
+  @Test
+  public void testRelativeUri() throws Exception {
+    thrown.expect(URISyntaxException.class);
+    thrown.expectMessage("no protocol");
+    new ValidatedUri("foo/bar");
+  }
+
   @Test
   public void testUnknownProtocol() throws Exception {
     thrown.expect(URISyntaxException.class);
@@ -66,15 +70,24 @@ public void testBadProtocol() throws Exception {
   }
 
   @Test
-  public void testNoHost() throws Exception {
+  public void testNoHostOrPath() throws Exception {
     thrown.expect(URISyntaxException.class);
+    thrown.expectMessage("Expected authority");
     new ValidatedUri("http://");
   }
 
   @Test
-  public void testRelativeUri() throws Exception {
+  public void testNoHost() throws Exception {
     thrown.expect(URISyntaxException.class);
-    new ValidatedUri("foo/bar");
+    thrown.expectMessage("no host");
+    new ValidatedUri("http:///foo/bar");
+  }
+
+  @Test
+  public void testNoAuthority() throws Exception {
+    thrown.expect(URISyntaxException.class);
+    thrown.expectMessage("no host");
+    new ValidatedUri("file:/foo/bar");
   }
 
   @Test
@@ -107,6 +120,15 @@ public void testRootPath() throws Exception {
         new ValidatedUri("http://foo:80/").getUri());
   }
 
+  @Test
+  public void testUnderscoreInHostName() throws Exception {
+    // new URI("http://foo_bar/baz") parses incorrectly, but does not throw a
+    // URISyntaxException. The host part, however, is discarded. So our check
+    // for missing host should catch this.
+    thrown.expect(URISyntaxException.class);
+    new ValidatedUri("http://foo_bar/baz").getUri();
+  }
+
   @Test
   public void testGetUri() throws Exception {
     assertEquals(new URI("http://example.com/foo/bar"),
@@ -128,29 +150,4 @@ public void testUnreachableHost() throws Exception {
     new ValidatedUri("http://unknown-host/foo/bar").logUnreachableHost();
     assertEquals(messages.toString(), 1, messages.size());
   }
-
-  /**
-   * Enables logging and captures matching log messages. The messages
-   * will not be localized or formatted.
-   *
-   * @param clazz the class to enable logging for
-   * @param substring capture log messages containing this substring
-   * @param output captured messages will be added to this collection
-   */
-  public static void captureLogMessages(Class<?> clazz,
-      final String substring, final Collection<? super String> output) {
-    Logger logger = Logger.getLogger(clazz.getName());
-    logger.setLevel(Level.ALL);
-
-    logger.addHandler(new Handler() {
-        @Override public void close() {}
-        @Override public void flush() {}
-
-        @Override public void publish(LogRecord record) {
-          if (record.getMessage().contains(substring)) {
-            output.add(record.getMessage());
-          }
-        }
-      });
-  }
 }