diff --git a/min/config.php b/min/config.php
index 040908e..cbb9fa9 100644
--- a/min/config.php
+++ b/min/config.php
@@ -45,9 +45,10 @@ $min_enableBuilder = true;
 
 
 /**
- * On most servers, this can be left empty. On others, $_SERVER['DOCUMENT_ROOT']
- * may be misconfigured or missing. If so, set this to your full document
- * root path with no trailing slash.
+ * Leave an empty string to use PHP's $_SERVER['DOCUMENT_ROOT'].
+ *
+ * On some servers, this value may be misconfigured or missing. If so, set this 
+ * to your full document root path with no trailing slash.
  * E.g. '/home/accountname/public_html' or 'c:\\xampp\\htdocs'
  *
  * If /min/ is directly inside your document root, just uncomment the 
diff --git a/min_unit_tests/_inc.php b/min_unit_tests/_inc.php
index 1f99017..6c82808 100644
--- a/min_unit_tests/_inc.php
+++ b/min_unit_tests/_inc.php
@@ -4,9 +4,13 @@ require dirname(__FILE__) . '/../min/config.php';
 
 set_include_path($min_libPath . PATH_SEPARATOR . get_include_path());
 
+// set cache path and doc root if configured
 $minifyCachePath = isset($min_cachePath) 
     ? $min_cachePath 
     : '';
+if ($min_documentRoot) {
+    $_SERVER['DOCUMENT_ROOT'] = $min_documentRoot;
+}
 
 error_reporting(E_ALL | E_STRICT);
 ini_set('display_errors', 1);
diff --git a/min_unit_tests/_test_files/css/paths.css b/min_unit_tests/_test_files/css/paths_prepend.css
similarity index 100%
rename from min_unit_tests/_test_files/css/paths.css
rename to min_unit_tests/_test_files/css/paths_prepend.css
diff --git a/min_unit_tests/_test_files/css/paths.min.css b/min_unit_tests/_test_files/css/paths_prepend.min.css
similarity index 100%
rename from min_unit_tests/_test_files/css/paths.min.css
rename to min_unit_tests/_test_files/css/paths_prepend.min.css
diff --git a/min_unit_tests/_test_files/css/paths_rewrite.css b/min_unit_tests/_test_files/css/paths_rewrite.css
new file mode 100644
index 0000000..aa41d0a
--- /dev/null
+++ b/min_unit_tests/_test_files/css/paths_rewrite.css
@@ -0,0 +1,14 @@
+@import "foo.css";
+@import 'bar/foo.css' print;
+@import '../bar/foo.css' print;
+@import '../../foo.css' print;
+@import '/css/foo.css'; /* abs, should not alter */
+@import 'http://foo.com/css/foo.css'; /* abs, should not alter */
+@import url(../foo.css) tv, projection;
+@import url("/css/foo.css"); /* abs, should not alter */
+@import url(/css2/foo.css); /* abs, should not alter */
+@import url(data:image/gif;base64,AAAA); /* data, should not alter */
+foo {background:url('bar/foo.png')}
+foo {background:url('http://foo.com/css/foo.css');} /* abs, should not alter */
+foo {background:url("//foo.com/css/foo.css");} /* protocol relative, should not alter */
+foo {background:url(data:image/gif;base64,AAAA);} /* data, should not alter */
\ No newline at end of file
diff --git a/min_unit_tests/_test_files/css/paths_rewrite.min.css b/min_unit_tests/_test_files/css/paths_rewrite.min.css
new file mode 100644
index 0000000..3493615
--- /dev/null
+++ b/min_unit_tests/_test_files/css/paths_rewrite.min.css
@@ -0,0 +1 @@
+@import "/_test_files/css/foo.css";@import '/_test_files/css/bar/foo.css' print;@import '/_test_files/bar/foo.css' print;@import '/foo.css' print;@import '/css/foo.css';@import 'http://foo.com/css/foo.css';@import url(/_test_files/foo.css) tv, projection;@import url("/css/foo.css");@import url(/css2/foo.css);@import url(data:image/gif;base64,AAAA);foo{background:url('/_test_files/css/bar/foo.png')}foo{background:url('http://foo.com/css/foo.css')}foo{background:url("//foo.com/css/foo.css")}foo{background:url(data:image/gif;base64,AAAA)}
\ No newline at end of file
diff --git a/min_unit_tests/_test_files/css/styles.css b/min_unit_tests/_test_files/css/styles.css
index 32d4b7f..bf46c0a 100644
--- a/min_unit_tests/_test_files/css/styles.css
+++ b/min_unit_tests/_test_files/css/styles.css
@@ -1,6 +1,6 @@
 /* some CSS to try to exercise things in general */
 
-@import     url( more.css );
+@import     url( /more.css );
 
     body, td, th {
         font-family: Verdana , "Bitstream Vera Sans" , sans-serif ;
diff --git a/min_unit_tests/_test_files/css/styles.min.css b/min_unit_tests/_test_files/css/styles.min.css
index e29908d..a823b05 100644
--- a/min_unit_tests/_test_files/css/styles.min.css
+++ b/min_unit_tests/_test_files/css/styles.min.css
@@ -1,3 +1,3 @@
-@import url(more.css);body,td,th{font-family:Verdana,"Bitstream Vera Sans",sans-serif;font-size:12px}.nav{margin-left:20%}#main-nav{background-color:red;border:1px
+@import url(/more.css);body,td,th{font-family:Verdana,"Bitstream Vera Sans",sans-serif;font-size:12px}.nav{margin-left:20%}#main-nav{background-color:red;border:1px
 solid #0f7}div#content
 h1+p{padding-top:0;margin-top:0}@media all and (min-width: 640px){#media-queries-1{background-color:#0f0}}@media screen and (max-width: 2000px){#media-queries-2{background-color:#0f0}}
\ No newline at end of file
diff --git a/min_unit_tests/_test_files/importProcessor/output.css b/min_unit_tests/_test_files/importProcessor/output.css
index c2b1095..1e4358c 100644
--- a/min_unit_tests/_test_files/importProcessor/output.css
+++ b/min_unit_tests/_test_files/importProcessor/output.css
@@ -1,7 +1,7 @@
 @media screen {
 /* some CSS to try to exercise things in general */
 
-@import     url(%TEST_FILES_URI%/css/more.css);
+@import     url(/more.css);
 
     body, td, th {
         font-family: Verdana , "Bitstream Vera Sans" , sans-serif ;
diff --git a/min_unit_tests/_test_files/minify/minified.css b/min_unit_tests/_test_files/minify/minified.css
index dc3a23e..0c36a5a 100644
--- a/min_unit_tests/_test_files/minify/minified.css
+++ b/min_unit_tests/_test_files/minify/minified.css
@@ -1,20 +1,4 @@
-@import url(%PATH_TO_WEB_TEST%/_test_files/css/more.css);body,td,th{font-family:Verdana,"Bitstream Vera Sans",sans-serif;font-size:12px}.nav{margin-left:20%}#main-nav{background-color:red;border:1px
+@import url(/more.css);body,td,th{font-family:Verdana,"Bitstream Vera Sans",sans-serif;font-size:12px}.nav{margin-left:20%}#main-nav{background-color:red;border:1px
 solid #0f7}div#content
-h1+p{padding-top:0;margin-top:0}@media all and (min-width: 640px){#media-queries-1{background-color:#0f0}}@media screen and (max-width: 2000px){#media-queries-2{background-color:#0f0}}.float-l{float:left}.form-suggest{height:200px;background:#DEE2D0;vertical-align:top}.form-input
-input{font-size:10px}.hide{display:none}.form-input
-textarea{font-size:11px;width:350px}.form-label{font-size:10px;font-weight:bold;line-height:25px;padding-right:10px;text-align:right;width:100px;color:#39738F}.font-9{font-size:9px}.form-topic{font-weight:bold}.form-error{color:red}.inline{display:inline}.space-10{clear:both;font-size:10px;height:10px;line-height:10px}.suggest-success{color:green;padding-left:10px;font-size:11px;font-weight:bold}.top{vertical-align:top}table
-td{padding:3px}a:link,a:active,a:visited,a.postlink{color:#069;text-decoration:none}a:hover{color:#DD6900}a.admin:hover,a.mod:hover{color:#DD6900}a.but,a.but:hover,a.but:visited{color:#000;text-decoration:none}a.topictitle:visited{color:#5493B4}a.topictitle:hover{color:#DD6900}body{color:#000;font:11px Verdana,Arial,Helvetica,sans-serif;margin:0
-10px 10px 10px;padding:0;overflow:auto}font,th,td,p{font:12px Verdana,Arial,Helvetica,sans-serif}form{display:inline}hr{border:0px
-solid #FFF;border-top-width:1px;height:0px}img{border:0
-solid}input{font:11px Verdana,Arial,Helvetica,sans-serif}input.button,input.liteoption,.fakebut{background:#FAFAFA;border:1px
-solid #000;font-size:11px}input.catbutton{background:#FAFAFA;border:1px
-solid #000;font-size:10px}input.mainoption{background:#FAFAFA;border:1px
-solid #000;font-size:11px;font-weight:bold}input.post,textarea.post{background:#FFF;border:1px
-solid #000;font:11px Verdana,Arial,Helvetica,sans-serif;padding-bottom:2px;padding-left:2px}select{background:#FFF;font:11px Verdana,Arial,Helvetica,sans-serif}table{text-align:left}td{vertical-align:middle}td.cat{background-color:#C2C6BA;font-weight:bold;height:20px;letter-spacing:1px;text-indent:4px}td.genmed,.genmed{font-size:11px}td.rowpic{background:#C2C6BA}td.spacerow{background:#E5E6E2}th{background-color:#FADD31;background-image:url(%PATH_TO_WEB_TEST%/_test_files/css/images/cellpic3.gif);background-repeat:repeat-x;color:#68685E;font-size:11px;font-weight:bold;line-height:16px;height:16px;padding-left:8px;padding-right:8px;text-align:center;white-space:nowrap}.admin,.mod{font-size:11px;font-weight:bold}.admin,a.admin,a.admin:visited{color:#FFA34F}.bodyline{background:#FFF;border:1px
-solid #98AAB1}.center{text-align:center}.code{background:#FAFAFA;border:1px
-solid #D1D7DC;color:#060;font:12px Courier,"Courier New",sans-serif;padding:5px}.errorline{background:#E5E6E2;border:1px
-solid #8F8B8B;color:#D92A2A}.explaintitle{color:#5C81B1;font-size:11px;font-weight:bold}.forumline{background:#FFF}.gensmall{font-size:10px}.h1-font{color:#069;display:inline;font:bold 13px Verdana,Arial,Helvetica,sans-serif;margin:0;text-decoration:none}.h2-font{display:inline;font-family:Verdana,Arial,Helvetica,sans-serif;font-size:11px}.height1{height:1px}.height22{height:22px}.height25{height:25px}.height28{height:28px}.height30{height:30px}.height40{height:40px}.helpline{border:0
-solid;font-size:10px}.imgfolder{margin:1px
-4px 1px 4px}.imgspace{margin-left:1px;margin-right:2px}.imgtopic,.imgicon{margin-left:3px}.left{text-align:left}.maintitle,h1,h2{color:#5C81B1;font:bold 20px/120% "Trebuchet MS",Verdana,Arial,Helvetica,sans-serif;text-decoration:none}.maxwidth{width:100%}.mod,a.mod,a.mod:visited{color:#060}.name{font-size:11px;font-weight:bold}.nav{font-size:11px;font-weight:bold}.nowrap{white-space:nowrap}.postbody{font-size:12px;line-height:125%}.postbody
-a{text-decoration:underline}.postdetails{color:#00396A;font-size:10px}.quote{background:#F3F3EF;border:1px
-solid #C2C6BA;color:#069;font-size:11px;line-height:125%}.right{text-align:right}.row1{background:#F0F0EB}.row2,.helpline{background:#E5E6E2}.row3{background:#DBDBD4}.subtitle,h2{font:bold 18px/180% "Trebuchet MS",Verdana,Arial,Helvetica,sans-serif;text-decoration:none}.topictitle{color:#000;font-size:11px;font-weight:bold}.underline{text-decoration:underline}.top{vertical-align:top}.image-hspace{margin-right:3px}.clear{clear:both}
\ No newline at end of file
+h1+p{padding-top:0;margin-top:0}@media all and (min-width: 640px){#media-queries-1{background-color:#0f0}}@media screen and (max-width: 2000px){#media-queries-2{background-color:#0f0}}
+/* YUI Compressor style comments are preserved */
diff --git a/min_unit_tests/test_Minify.php b/min_unit_tests/test_Minify.php
index 5c6429c..8b5184f 100644
--- a/min_unit_tests/test_Minify.php
+++ b/min_unit_tests/test_Minify.php
@@ -120,16 +120,7 @@ function test_Minify()
     // don't allow conditional headers
     unset($_SERVER['HTTP_IF_NONE_MATCH'], $_SERVER['HTTP_IF_MODIFIED_SINCE']);
 
-    $pathToWebTest = str_replace(
-        DIRECTORY_SEPARATOR
-        ,'/'
-        ,substr(dirname(__FILE__), strlen(realpath($_SERVER['DOCUMENT_ROOT'])))
-    );
-    $expectedContent = str_replace(
-        '%PATH_TO_WEB_TEST%'
-        ,$pathToWebTest
-        ,file_get_contents($minifyTestPath . '/minified.css')
-    );
+    $expectedContent = file_get_contents($minifyTestPath . '/minified.css');
 
     $expected = array(
         'success' => true
@@ -146,7 +137,7 @@ function test_Minify()
     $output = Minify::serve('Files', array(
         'files' => array(
             $thisDir . '/_test_files/css/styles.css'
-            ,$thisDir . '/_test_files/css/subsilver.css'
+            ,$thisDir . '/_test_files/css/comments.css'
         )
         ,'quiet' => true
         ,'lastModifiedTime' => $lastModified
diff --git a/min_unit_tests/test_Minify_Build.php b/min_unit_tests/test_Minify_Build.php
index b4e3677..f68f519 100644
--- a/min_unit_tests/test_Minify_Build.php
+++ b/min_unit_tests/test_Minify_Build.php
@@ -7,7 +7,7 @@ function test_Minify_Build()
 {
     global $thisDir;
     
-    $file1 = $thisDir . '/_test_files/css/paths.css';
+    $file1 = $thisDir . '/_test_files/css/paths_prepend.css';
     $file2 = $thisDir . '/_test_files/css/styles.css';
     $maxTime = max(filemtime($file1), filemtime($file2));
     
diff --git a/min_unit_tests/test_Minify_CSS.php b/min_unit_tests/test_Minify_CSS.php
index 1b4841e..96e1875 100644
--- a/min_unit_tests/test_Minify_CSS.php
+++ b/min_unit_tests/test_Minify_CSS.php
@@ -20,13 +20,24 @@ function test_CSS()
     
     foreach ($list as $item) {
     
-        $options = ($item === 'paths') 
-            ? array('prependRelativePath' => '../')
-            : array();
+        $options = array();
+        if ($item === 'paths_prepend') {
+            $options = array('prependRelativePath' => '../');
+        } elseif ($item === 'paths_rewrite') {
+            $options = array('currentDir' => $thisDir . '/_test_files/css');
+            $tempDocRoot = $_SERVER['DOCUMENT_ROOT'];
+            $_SERVER['DOCUMENT_ROOT'] = $thisDir;
+        }
         
         $src = file_get_contents($cssPath . "/{$item}.css");
         $minExpected = file_get_contents($cssPath . "/{$item}.min.css");
         $minOutput = Minify_CSS::minify($src, $options);
+        
+        // reset doc root as configured
+        if ($item === 'paths_rewrite') {
+            $_SERVER['DOCUMENT_ROOT'] = $tempDocRoot;
+        }
+        
         $passed = assertTrue($minExpected === $minOutput, 'Minify_CSS : ' . $item);
         
         if (__FILE__ === realpath($_SERVER['SCRIPT_FILENAME'])) {
diff --git a/min_unit_tests/test_Minify_CSS_UriRewriter.php b/min_unit_tests/test_Minify_CSS_UriRewriter.php
index 5259f16..704ab01 100644
--- a/min_unit_tests/test_Minify_CSS_UriRewriter.php
+++ b/min_unit_tests/test_Minify_CSS_UriRewriter.php
@@ -13,8 +13,8 @@ function test_Minify_CSS_UriRewriter()
     
     $actual = Minify_CSS_UriRewriter::rewrite(
         $in
-        ,$thisDir . '/_test_files/css_uriRewriter'
-        ,$thisDir
+        ,$thisDir . '/_test_files/css_uriRewriter' // currentDir
+        ,$thisDir // use DOCUMENT_ROOT = '/full/path/to/min_unit_tests'
     );
     
     $passed = assertTrue($expected === $actual, 'Minify_CSS_UriRewriter');
diff --git a/min_unit_tests/test_environment.php b/min_unit_tests/test_environment.php
index 94b3af3..f801569 100644
--- a/min_unit_tests/test_environment.php
+++ b/min_unit_tests/test_environment.php
@@ -25,18 +25,24 @@ function test_environment()
         0 === preg_match('@[\\\\/]$@', $_SERVER['DOCUMENT_ROOT'])
         ,'environment : DOCUMENT_ROOT should not end in trailing slash'
     );
-    $goodRoot = assertTrue(
-        0 === strpos(realpath(__FILE__), realpath($_SERVER['DOCUMENT_ROOT']))
-        ,'environment : DOCUMENT_ROOT should be real path and contain this test file'
+    $isRealPath = assertTrue(false !== realpath($_SERVER['DOCUMENT_ROOT'])
+        ,'environment : DOCUMENT_ROOT should pass realpath()'
     );
-    if (! $noSlash || ! $goodRoot) {
-        echo "!NOTE: environment : If you cannot modify DOCUMENT_ROOT, consider "
-           . "setting \$min_documentRoot in config.php\n";
+    $containsThisFile = assertTrue(
+        0 === strpos(realpath(__FILE__), realpath($_SERVER['DOCUMENT_ROOT']))
+        ,'environment : DOCUMENT_ROOT should contain this test file'
+    );
+    if (! $noSlash || ! $isRealPath || ! $containsThisFile) {
+        echo "\nDOCUMENT_ROOT is set to: '{$_SERVER['DOCUMENT_ROOT']}'. If you "
+           . "cannot modify this, consider setting \$min_documentRoot in config.php\n\n";
     }
     if (isset($_SERVER['SUBDOMAIN_DOCUMENT_ROOT'])) {
-        echo "!NOTE: environment : \$_SERVER['SUBDOMAIN_DOCUMENT_ROOT'] is set. "
+        echo "\n!NOTE: environment : \$_SERVER['SUBDOMAIN_DOCUMENT_ROOT'] is set. "
            . "You may need to set \$min_documentRoot to this in config.php\n";
     }
+    if (realpath(__FILE__) !== realpath($_SERVER['DOCUMENT_ROOT'] . '/min_unit_tests/test_environment.php')) {
+        echo "!NOTE: environment : /min_unit_tests/ is not directly inside DOCUMENT_ROOT\n";
+    }
 
     $thisUrl = 'http://'
         . $_SERVER['HTTP_HOST'] // avoid redirects when SERVER_NAME doesn't match