diff --git a/karma-tests/dummy.html b/karma-tests/dummy.html
new file mode 100644
index 00000000..52e695fa
--- /dev/null
+++ b/karma-tests/dummy.html
@@ -0,0 +1,9 @@
+<html>
+<head><meta charset="UTF-8"></head>
+<body>
+	<!-- This is a dummy page used in
+	     tests of Wombat's live-rewriting
+		 functionality.
+	!-->
+</body>
+</html>
diff --git a/karma-tests/karma.conf.js b/karma-tests/karma.conf.js
index 2d482d5c..9972fac9 100644
--- a/karma-tests/karma.conf.js
+++ b/karma-tests/karma.conf.js
@@ -28,18 +28,10 @@ var sauceLaunchers = {
         version: '9.0',
     },
 
-/*  Edge is currently broken in
-    pywb.
-
-    See: https://github.com/ikreymer/pywb/issues/148 (Edge)
-         https://github.com/ikreymer/pywb/issues/147 (Safari)
-
-
     sl_edge: {
         base: 'SauceLabs',
         browserName: 'MicrosoftEdge',
     },
-*/
 };
 
 var localLaunchers = {
@@ -73,6 +65,11 @@ module.exports = function(config) {
         included: false,
         served: true,
       },
+      {
+        pattern: 'karma-tests/dummy.html',
+        included: false,
+        served: true,
+      },
       'karma-tests/*.spec.js',
     ],
 
@@ -90,12 +87,15 @@ module.exports = function(config) {
 
     sauceLabs: sauceLabsConfig,
 
-    // use an extended timeout for capturing Sauce Labs
-    // browsers and waiting for activity
-    // in case the service is busy
+    // Set extended timeouts to account for the slowness
+    // in connecting to remote browsers (eg. when using
+    // Sauce Labs)
+    //
+    // See https://oligofren.wordpress.com/2014/05/27/running-karma-tests-on-browserstack/
     captureTimeout: 3 * 60000,
-
     browserNoActivityTimeout: 30 * 1000,
+    browserDisconnectTimeout: 10 * 1000,
+    browserDisconnectTolerance: 1,
 
     customLaunchers: customLaunchers,
 
diff --git a/karma-tests/wombat.spec.js b/karma-tests/wombat.spec.js
index 62fe9f72..fbb9b33d 100644
--- a/karma-tests/wombat.spec.js
+++ b/karma-tests/wombat.spec.js
@@ -1,4 +1,3 @@
-var WOMBAT_SRC = '../pywb/static/wombat.js';
 var DEFAULT_TIMEOUT = 20000;
 
 // creates a new document in an <iframe> and runs
@@ -12,7 +11,7 @@ var DEFAULT_TIMEOUT = 20000;
 function runWombatTest(testCase, done) {
     // create an <iframe>
     var testFrame = document.createElement('iframe');
-    testFrame.src = '/dummy.html';
+    testFrame.src = '/base/karma-tests/dummy.html';
     document.body.appendChild(testFrame);
 
     testFrame.contentWindow.addEventListener('load', function () {
@@ -27,8 +26,20 @@ function runWombatTest(testCase, done) {
             done(new Error(ex));
         };
 
-        // expose chai assertions to the <iframe>
-        window.assert = assert;
+        // expose utility methods for assertion testing in tests.
+        // (We used to expose chai asserts here but Karma's default
+        //  error reporter replaces URLs in exception messages with
+        //  the corresponding file paths, which is unhelpful for us
+        //  since assert.equal() will often be called with URLs in our tests)
+        window.assert = {
+            equal: function (a, b) {
+                if (a !== b) {
+                    x.equal(a, b);
+                    console.error('Mismatch between', a, 'and', b);
+                    throw new Error('AssertionError');
+                }
+            }
+        };
 
         runFunctionInIFrame(function () {
             // re-assign the iframe's console object to the parent window's
@@ -136,7 +147,7 @@ describe('WombatJS', function () {
                 testScript: function () {
                     var link = document.getElementById('link');
                     if (domTests.areDOMPropertiesConfigurable()) {
-                        assert.equal(link.href, 'http:///foobar.html');
+                        assert.equal(link.href, 'http:///base/karma-tests/foobar.html');
                     }
                 },
             }, done);
@@ -160,7 +171,7 @@ describe('WombatJS', function () {
                         throw new Error('baseURI is not a string');
                     }
                     if (domTests.areDOMPropertiesConfigurable()) {
-                        assert.equal(baseURI, 'http:///dummy.html');
+                        assert.equal(baseURI, 'http:///base/karma-tests/dummy.html');
                     }
                 },
             }, done);
