diff --git includes/common.inc includes/common.inc
index 896147b..b8374e9 100644
--- includes/common.inc
+++ includes/common.inc
@@ -3059,8 +3059,7 @@ function drupal_load_stylesheet_content($contents, $optimize = FALSE) {
     // Perform some safe CSS optimizations.
     $contents = preg_replace('<
       \s*([@{}:;,]|\)\s|\s\()\s* |  # Remove whitespace around separators, but keep space around parentheses.
-      /\*([^*\\\\]|\*(?!/))+\*/ |   # Remove comments that are not CSS hacks.
-      [\n\r]                        # Remove line breaks.
+      /\*([^*\\\\]|\*(?!/))+\*/     # Remove comments that are not CSS hacks.
       >x', '\1', $contents);
   }
 
diff --git modules/simpletest/files/css_test_files/css_input_without_import.css modules/simpletest/files/css_test_files/css_input_without_import.css
new file mode 100644
index 0000000..a821094
--- /dev/null
+++ modules/simpletest/files/css_test_files/css_input_without_import.css
@@ -0,0 +1,38 @@
+/* $Id$ */
+
+/**
+ * @file Basic css that does not use import
+ */
+
+
+body {
+  margin: 0;
+  padding: 0;
+  background: #edf5fa;
+  font: 76%/170% Verdana, sans-serif;
+  color: #494949;
+}
+
+.this .is .a .test {
+  font: 1em/100% Verdana, sans-serif;
+  color: #494949;
+}
+
+/**
+ * CSS spec says that all whitespace is valid whitespace, so this selector should be just as
+ * good as the one above.
+ */
+ 
+.this
+.is
+.a
+.test {
+font: 1em/100% Verdana, sans-serif;
+color: #494949;
+}
+
+textarea, select {
+  font: 1em/160% Verdana, sans-serif;
+  color: #494949;
+}
+
diff --git modules/simpletest/files/css_test_files/css_input_without_import.css.optimized.css modules/simpletest/files/css_test_files/css_input_without_import.css.optimized.css
new file mode 100644
index 0000000..bf139f4
--- /dev/null
+++ modules/simpletest/files/css_test_files/css_input_without_import.css.optimized.css
@@ -0,0 +1,11 @@
+
+
+
+
+
+body{margin:0;padding:0;background:#edf5fa;font:76%/170% Verdana,sans-serif;color:#494949;}.this .is .a .test{font:1em/100% Verdana,sans-serif;color:#494949;}
+ 
+.this
+.is
+.a
+.test{font:1em/100% Verdana,sans-serif;color:#494949;}textarea,select{font:1em/160% Verdana,sans-serif;color:#494949;}
\ No newline at end of file
diff --git modules/simpletest/files/css_test_files/css_input_without_import.css.unoptimized.css modules/simpletest/files/css_test_files/css_input_without_import.css.unoptimized.css
new file mode 100644
index 0000000..a821094
--- /dev/null
+++ modules/simpletest/files/css_test_files/css_input_without_import.css.unoptimized.css
@@ -0,0 +1,38 @@
+/* $Id$ */
+
+/**
+ * @file Basic css that does not use import
+ */
+
+
+body {
+  margin: 0;
+  padding: 0;
+  background: #edf5fa;
+  font: 76%/170% Verdana, sans-serif;
+  color: #494949;
+}
+
+.this .is .a .test {
+  font: 1em/100% Verdana, sans-serif;
+  color: #494949;
+}
+
+/**
+ * CSS spec says that all whitespace is valid whitespace, so this selector should be just as
+ * good as the one above.
+ */
+ 
+.this
+.is
+.a
+.test {
+font: 1em/100% Verdana, sans-serif;
+color: #494949;
+}
+
+textarea, select {
+  font: 1em/160% Verdana, sans-serif;
+  color: #494949;
+}
+
diff --git modules/simpletest/tests/common.test modules/simpletest/tests/common.test
index 0c667d9..bc0d60d 100644
--- modules/simpletest/tests/common.test
+++ modules/simpletest/tests/common.test
@@ -563,6 +563,51 @@ class CascadingStylesheetsTestCase extends DrupalWebTestCase {
   }
 }
 
+
+/**
+ * CSS Unit Tests.
+ */
+class CascadingStylesheetsUnitTestCase extends DrupalWebTestCase {
+  public static function getInfo() {
+    return array(
+      'name' => 'CSS Unit Tests',
+      'description' => 'Unit tests on CSS functions like aggregation.',
+      'group' => 'System',
+    );
+  }
+
+  /**
+   * Tests basic CSS loading with and without optimization
+   * (drupal_load_stylesheet()).
+   * This can be enhanced by adding additional css files with variant test cases.
+   * Currently, this is specifically testing to make sure that whitespace
+   * is treated with adequate respect (not arbitrarily removing linefeeds).
+   */
+  function testLoadCssBasic() {
+    /**
+     * Array of files to test. Original = .css,
+     * unoptimized expected output = .css.unoptimized.css,
+     * optimized expected = .css.optimized.css
+     * They live in the simpletest/files/css_test_files directory
+     */
+    $testfiles = array('css_input_without_import.css', );
+    $path = drupal_get_path('module', 'simpletest') . '/files/css_test_files';
+    foreach ($testfiles as $file) {
+      $expected = file_get_contents("$path/$file.unoptimized.css");
+      $unoptimized_output = drupal_load_stylesheet("$path/$file", FALSE);
+      $this->assertEqual($unoptimized_output, $expected,
+        t('Loaded CSS Stylesheet has expected contents (unoptimized) (@file)',
+          array('@file' => $file)));
+      $expected = file_get_contents("$path/$file.optimized.css");
+      $optimized_output = drupal_load_stylesheet("$path/$file", TRUE);
+      $this->assertEqual($optimized_output, $expected,
+        t('Loaded CSS Stylesheet has expected contents (optimized) (@file)',
+          array('@file' => $file)));
+    }
+  }
+}
+
+
 /**
  * Test drupal_http_request().
  */