diff --git a/test/cases/at-import/a.css b/test/cases/at-import/a.css
new file mode 100644
index 00000000..34ce1e9c
--- /dev/null
+++ b/test/cases/at-import/a.css
@@ -0,0 +1,9 @@
+@import './ae.css';
+@import './aa.css';
+@import './ab.css';
+@import './ac.css';
+@import './ad.css';
+
+body {
+  background: red;
+}
diff --git a/test/cases/at-import/aa.css b/test/cases/at-import/aa.css
new file mode 100644
index 00000000..9ad34057
--- /dev/null
+++ b/test/cases/at-import/aa.css
@@ -0,0 +1,3 @@
+.aa {
+  background: green;
+}
diff --git a/test/cases/at-import/ab.css b/test/cases/at-import/ab.css
new file mode 100644
index 00000000..a57f2508
--- /dev/null
+++ b/test/cases/at-import/ab.css
@@ -0,0 +1,3 @@
+.ab {
+  background: green;
+}
diff --git a/test/cases/at-import/ac.css b/test/cases/at-import/ac.css
new file mode 100644
index 00000000..356d5138
--- /dev/null
+++ b/test/cases/at-import/ac.css
@@ -0,0 +1,3 @@
+.ac {
+  background: green;
+}
diff --git a/test/cases/at-import/ad.css b/test/cases/at-import/ad.css
new file mode 100644
index 00000000..1323e35d
--- /dev/null
+++ b/test/cases/at-import/ad.css
@@ -0,0 +1,3 @@
+.ad {
+  background: green;
+}
diff --git a/test/cases/at-import/ae.css b/test/cases/at-import/ae.css
new file mode 100644
index 00000000..5eca6b0e
--- /dev/null
+++ b/test/cases/at-import/ae.css
@@ -0,0 +1,3 @@
+.ae {
+  background: green;
+}
diff --git a/test/cases/at-import/b.css b/test/cases/at-import/b.css
new file mode 100644
index 00000000..e300b655
--- /dev/null
+++ b/test/cases/at-import/b.css
@@ -0,0 +1,6 @@
+@import './ba.css';
+@import './bb.css';
+
+body {
+  background: yellow;
+}
diff --git a/test/cases/at-import/ba.css b/test/cases/at-import/ba.css
new file mode 100644
index 00000000..adb84dbe
--- /dev/null
+++ b/test/cases/at-import/ba.css
@@ -0,0 +1,3 @@
+.ba {
+  background: green;
+}
diff --git a/test/cases/at-import/bb.css b/test/cases/at-import/bb.css
new file mode 100644
index 00000000..1e09c7ac
--- /dev/null
+++ b/test/cases/at-import/bb.css
@@ -0,0 +1,3 @@
+.bb {
+  background: green;
+}
diff --git a/test/cases/at-import/expected/main.css b/test/cases/at-import/expected/main.css
new file mode 100644
index 00000000..eb4811b4
--- /dev/null
+++ b/test/cases/at-import/expected/main.css
@@ -0,0 +1,36 @@
+.ae {
+  background: green;
+}
+
+.aa {
+  background: green;
+}
+
+.ab {
+  background: green;
+}
+
+.ac {
+  background: green;
+}
+
+.ad {
+  background: green;
+}
+
+body {
+  background: red;
+}
+
+.ba {
+  background: green;
+}
+
+.bb {
+  background: green;
+}
+
+body {
+  background: yellow;
+}
+
diff --git a/test/cases/at-import/index.js b/test/cases/at-import/index.js
new file mode 100644
index 00000000..a0ec7954
--- /dev/null
+++ b/test/cases/at-import/index.js
@@ -0,0 +1,2 @@
+import './a.css';
+import './b.css';
diff --git a/test/cases/at-import/webpack.config.js b/test/cases/at-import/webpack.config.js
new file mode 100644
index 00000000..a22ebdad
--- /dev/null
+++ b/test/cases/at-import/webpack.config.js
@@ -0,0 +1,21 @@
+const Self = require('../../../');
+
+module.exports = {
+  entry: './index.js',
+  module: {
+    rules: [
+      {
+        test: /\.css$/,
+        use: [
+          Self.loader,
+          'css-loader',
+        ],
+      },
+    ],
+  },
+  plugins: [
+    new Self({
+      filename: '[name].css',
+    }),
+  ],
+};
diff --git a/test/cases/css-import/a.css b/test/cases/css-import/a.css
new file mode 100644
index 00000000..31fc5b8a
--- /dev/null
+++ b/test/cases/css-import/a.css
@@ -0,0 +1 @@
+body { background: red; }
diff --git a/test/cases/css-import/b.css b/test/cases/css-import/b.css
new file mode 100644
index 00000000..11559583
--- /dev/null
+++ b/test/cases/css-import/b.css
@@ -0,0 +1,5 @@
+.b { background: red; }
+
+@import url("https://some/external/css");
+
+.b { color: yellow; }
diff --git a/test/cases/css-import/c.css b/test/cases/css-import/c.css
new file mode 100644
index 00000000..9c41dd1f
--- /dev/null
+++ b/test/cases/css-import/c.css
@@ -0,0 +1,5 @@
+.c { background: red; }
+@import './a.css';
+@import url("https://some/other/external/css");
+
+.c { color: yellow; }
diff --git a/test/cases/css-import/expected/main.css b/test/cases/css-import/expected/main.css
new file mode 100644
index 00000000..cd5dacee
--- /dev/null
+++ b/test/cases/css-import/expected/main.css
@@ -0,0 +1,14 @@
+@import url(https://some/other/external/css);
+@import url(https://some/external/css);
+body { background: red; }
+
+.c { background: red; }
+
+.c { color: yellow; }
+
+.b { background: red; }
+
+.b { color: yellow; }
+
+
+
diff --git a/test/cases/css-import/index.css b/test/cases/css-import/index.css
new file mode 100644
index 00000000..c03e069d
--- /dev/null
+++ b/test/cases/css-import/index.css
@@ -0,0 +1,2 @@
+@import './c.css';
+@import './b.css';
diff --git a/test/cases/css-import/webpack.config.js b/test/cases/css-import/webpack.config.js
new file mode 100644
index 00000000..7442065a
--- /dev/null
+++ b/test/cases/css-import/webpack.config.js
@@ -0,0 +1,21 @@
+const Self = require('../../../');
+
+module.exports = {
+  entry: './index.css',
+  module: {
+    rules: [
+      {
+        test: /\.css$/,
+        use: [
+          Self.loader,
+          'css-loader',
+        ],
+      },
+    ],
+  },
+  plugins: [
+    new Self({
+      filename: '[name].css',
+    }),
+  ],
+};