Add a test with all the less docs and fix issues (#1792)

The docs go over a bunch of edge cases, might as well have it as a test :)

http://lesscss.org/features/

I just had to remove

```css
.weird-element {
  content: ^//* some horrible but needed css hack;
}
```

but i'm not sure if it's real less.

src/parser.js

@@ -310,18 +310,11 @@ function parseNestedCSS(node) {
         ? node.raws.selector.raw
         : node.selector;
 
-      if (selector.trim().endsWith(":")) {
+      try {
+        node.selector = parseSelector(selector);
+      } catch (e) {
+        // Fail silently. It's better to print it as is than to try and parse it
         node.selector = selector;
-      } else {
-        try {
-          node.selector = parseSelector(selector);
-        } catch (e) {
-          throw createError(
-            "(postcss-selector-parser) " + e.toString(),
-            node.source.start.line,
-            node.source.start.column - 1
-          );
-        }
       }
     }
     if (node.type && typeof node.value === "string") {
@@ -361,7 +354,7 @@ function parseWithPostCSSParser(parser, text) {
 
 function parseWithPostCSS(text) {
   const r = require;
-  const isLikelySCSS = text.match(/(\w\s*: [^}:]+|#){/);
+  const isLikelySCSS = !!text.match(/(\w\s*: [^}:]+|#){/);
   try {
     return parseWithPostCSSParser(
       r(isLikelySCSS ? "postcss-scss" : "postcss-less"),

src/printer.js

@@ -2545,6 +2545,7 @@ function genericPrintNoParens(path, options, print, args) {
     case "css-rule": {
       return concat([
         path.call(print, "selector"),
+        n.important ? " !important" : "",
         n.nodes
           ? concat([
               " {",
@@ -2597,7 +2598,14 @@ function genericPrintNoParens(path, options, print, args) {
       ]);
     }
     case "css-import": {
-      return concat(["@", n.name, " ", n.importPath, ";"]);
+      return concat([
+        "@",
+        n.name,
+        " ",
+        n.directives ? concat([n.directives, " "]) : "",
+        n.importPath,
+        ";"
+      ]);
     }
     // postcss-media-query-parser
     case "media-query-list": {
@@ -2675,7 +2683,7 @@ function genericPrintNoParens(path, options, print, args) {
       return concat([
         n.value,
         n.nodes && n.nodes.length > 0
-          ? concat(["(", concat(path.map(print, "nodes")), ")"])
+          ? concat(["(", join(", ", path.map(print, "nodes")), ")"])
           : ""
       ]);
     }

tests/css_import/__snapshots__/jsfmt.spec.js.snap

@@ -0,0 +1,8 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`directives.css 1`] = `
+@import (multiple) "foo.less";
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+@import (multiple) "foo.less";
+
+`;

tests/css_import/directives.css

@@ -0,0 +1 @@
+@import (multiple) "foo.less";

tests/css_import/jsfmt.spec.js

@@ -0,0 +1 @@
+run_spec(__dirname, { parser: "postcss" });

tests/css_important/__snapshots__/jsfmt.spec.js.snap

@@ -1,8 +1,20 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`important.css 1`] = `
-max-height: none !important;
+div {
+  max-height: none !important;
+}
+
+.important {
+  .foo() !important;
+}
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-max-height: none !important;
+div {
+  max-height: none !important;
+}
+
+.important {
+  .foo() !important;
+}
 
 `;

tests/css_important/important.css

@@ -1 +1,7 @@
-max-height: none !important;
+div {
+  max-height: none !important;
+}
+
+.important {
+  .foo() !important;
+}

tests/css_selector_call/__snapshots__/jsfmt.spec.js.snap

@@ -0,0 +1,9 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`call.css 1`] = `
+.e:extend(.f, .g) {}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.e:extend(.f, .g) {
+}
+
+`;

tests/css_selector_call/call.css

@@ -0,0 +1 @@
+.e:extend(.f, .g) {}

tests/css_selector_call/jsfmt.spec.js

@@ -0,0 +1 @@
+run_spec(__dirname, { parser: "postcss" });