Update specs to keep trailing comments on the previous line

See sass/dart-sass#417

lib/sass_spec/test.rb

@@ -499,22 +499,40 @@ def delete_test!
   def migrate_impl!
     if @status == 0
       if @test_case.expected != @normalized_output || @test_case.should_fail?
-        @test_case.write("output.css", @output, impl: true)
+        _write_for_impl("output.css", @output)
       end
 
       if extract_error_message(@test_case.expected_warning) != extract_error_message(@error)
-        @test_case.write("warning", @error, impl: true)
+        _write_for_impl("warning", @error)
       end
     else
       actual_error = @test_case.expected_error && extract_error_message(@test_case.expected_error)
       if actual_error != extract_error_message(@error)
-        @test_case.write("error", @error, impl: true)
+        _write_for_impl("error", @error)
       end
     end
 
     change_options(remove_warning_todo: [@test_case.impl], remove_todo: [@test_case.impl])
   end
 
+  # Writes `contents` to the implementation-specific version of `file`.
+  #
+  # If the current implementation is Dart Sass, this instead migrates the
+  # existing file to a LibSass-specific file and overwrites the default file
+  # with the Dart Sass expectation.
+  def _write_for_impl(file, contents)
+    if @test_case.impl != "dart-sass"
+      @test_case.write(file, contents, impl: true)
+      return
+    end
+
+    libsass_test_case = SassSpec::TestCase.new(@test_case.dir, "libsass")
+    libsass_test_case.write(file, libsass_test_case.read(file, impl: :auto), impl: true)
+
+    @test_case.delete(file, if_exists: true, impl: true)
+    @test_case.write(file, contents, impl: false)
+  end
+
   ## Other utilities
 
   # Returns whether the current test case is marked as TODO, but is still being

spec/basic/06_nesting_and_comments.hrx

@@ -65,6 +65,53 @@ div span {
   /* yet another comment that should be preserved */
   display: inline-block;
 }
+div span a {
+  text-decoration: none; /* where will this comment go? */
+  color: green;
+  /* what about this comment? */
+  border: 1px bloo blee red;
+}
+div empty not_empty {
+  blah: blah;
+  bloo: bloo;
+}
+div p {
+  padding: 10px 8%;
+  -webkit-box-sizing: hux;
+}
+div h1 {
+  color: "a 'red' and \"blue\" value";
+}
+
+/* last comment, top level again --
+   compare the indentation! */
+div {
+  f: g;
+}
+div empty span {
+  a: b;
+}
+div empty_with_comment {
+  /* hey now */
+}
+div empty_with_comment span {
+  c: d;
+}
+
+<===> output-libsass.css
+/* top level comment -- should be preserved */
+div {
+  /* another comment that should be preserved */
+  color: red;
+  background: blue;
+  /* the next selector should be indented two spaces */
+  margin: 10px 5px;
+}
+div span {
+  font-weight: bold;
+  /* yet another comment that should be preserved */
+  display: inline-block;
+}
 div span a {
   text-decoration: none;
   /* where will this comment go? */

spec/css/keyframes.hrx

@@ -5,6 +5,10 @@ a {
 }
 
 <===> bubble/empty/output.css
+@keyframes { /**/
+}
+
+<===> bubble/empty/output-libsass.css
 @keyframes {
   /**/
 }

spec/directives/use/css/order.hrx

@@ -451,6 +451,23 @@ a {file: midstream}
 
 <===> import_order/comments_and_imports/output.css
 /* upstream comment before import */
+@import "upstream.css"; /* midstream comment before use */
+/* midstream comment before first import */
+@import "midstream1.css";
+/* midstream comment before second import */
+@import "midstream2.css"; /* input comment before use */
+/* input comment before import */
+@import "input.css";
+/* upstream comment after import */
+/* midstream comment after imports */
+a {
+  file: midstream;
+}
+
+/* input comment after import */
+
+<===> import_order/comments_and_imports/output-libsass.css
+/* upstream comment before import */
 
 @import "upstream.css";
 

spec/libsass-closed-issues/issue_1007.hrx

@@ -4,6 +4,15 @@
 } /* end */
 <===> output.css
 /* start */
+foo baz {
+  /* before */
+  margin: 0; /* after */
+}
+
+/* end */
+
+<===> output-libsass.css
+/* start */
 foo baz {
   /* before */
   margin: 0;

spec/libsass-closed-issues/issue_1294.hrx

@@ -11,6 +11,14 @@ foo {
 /*------------------------------------*\
   #BUTTONS
 \*------------------------------------*/
+foo {
+  display: inline-block; /* [1] */
+}
+
+<===> output-libsass.css
+/*------------------------------------*\
+  #BUTTONS
+\*------------------------------------*/
 foo {
   display: inline-block;
   /* [1] */

spec/libsass-closed-issues/issue_1567.hrx

@@ -7,6 +7,14 @@
 
 <===> output.css
 /* any */
+@media screen, not print { /* whatever */
+  body {
+    line-height: 1.2;
+  }
+}
+
+<===> output-libsass.css
+/* any */
 @media screen, not print {
   /* whatever */
   body {

spec/libsass-closed-issues/issue_894.hrx

@@ -2,19 +2,18 @@
 a {/**/}
 b {content: 'something so I have a non-empty expected output'}
 <===> output.css
-a {
-  /**/
+a { /**/
 }
 
 b {
-  content: 'something so I have a non-empty expected output';
+  content: "something so I have a non-empty expected output";
 }
 
-<===> output-dart-sass.css
+<===> output-libsass.css
 a {
   /**/
 }
 
 b {
-  content: "something so I have a non-empty expected output";
+  content: 'something so I have a non-empty expected output';
 }

spec/libsass-closed-issues/issue_941.hrx

@@ -6,6 +6,12 @@
 
 <===> output.css
 .one,
+.two { /* 3 */
+  color: #F00; /* 4 */
+}
+
+<===> output-libsass.css
+.one,
 .two {
   /* 3 */
   color: #F00;