add charset tests (#109)

test/analyzer/atrules/atrules.js

@@ -0,0 +1,62 @@
+const test = require('ava')
+const analyze = require('../../../src/analyzer/atrules/charsets')
+
+const FIXTURE = [
+  {
+    type: 'charset',
+    params: 'B'
+  },
+  {
+    type: 'charset',
+    params: 'A'
+  },
+  {
+    type: 'charset',
+    params: 'A'
+  }
+]
+
+test('it responds with the correct structure', t => [
+  t.deepEqual(analyze([]), {
+    total: 0,
+    totalUnique: 0,
+    unique: []
+  })
+])
+
+test('it counts charsets', t => {
+  const {total: actual} = analyze(FIXTURE)
+
+  t.is(actual, 3)
+})
+
+test('it finds all unique charsets and counts and sorts them', t => {
+  const {unique: actual} = analyze(FIXTURE)
+
+  t.deepEqual(actual, [{count: 2, value: 'A'}, {value: 'B', count: 1}])
+})
+
+test('it counts unique charsets', t => {
+  const {totalUnique: actual} = analyze(FIXTURE)
+
+  t.is(actual, 2)
+})
+
+test('it does not report non-charset atrules as charset', t => {
+  const actual = analyze([
+    {
+      type: 'media',
+      params: 'X'
+    },
+    {
+      type: 'document',
+      params: 'X'
+    }
+  ])
+
+  t.deepEqual(actual, {
+    total: 0,
+    totalUnique: 0,
+    unique: []
+  })
+})