Add an unicity test for features. (#824)

And remove one duplicate

data/pc/common/features.json

@@ -289,14 +289,6 @@
     "description": "dimension is an nbt compound",
     "versions": ["1.16.2", "latest"]
   },
-  {
-    "name": "dimensionDataIsAvailable",
-    "description": "dimensionData is available, describing additional dimension information",
-    "versions": [
-      "1.17",
-      "latest"
-    ]
-  },
   {
     "name": "doesntHaveChestType",
     "description": "chests don't have a type property",

tools/js/test/test.js

@@ -57,4 +57,21 @@ minecraftTypes.forEach(function (type) {
       })
     })
   })
+  describe('features.json quality is good', function () {
+    it('there is no duplicate feature in features.json', () => {
+      const features = require('../../../data/' + type + '/common/features.json')
+      const countPerFeature = {}
+      for (const feature of features) {
+        countPerFeature[feature.name] = countPerFeature[feature.name] ? countPerFeature[feature.name] + 1 : 1
+      }
+      let duplicateCount = 0
+      for (const [name, count] of Object.entries(countPerFeature)) {
+        if (count > 1) {
+          console.log(`feature ${name} is duplicated ${count} times, please remove ${count - 1}`)
+          duplicateCount += 1
+        }
+      }
+      assert.equal(duplicateCount, 0, `${duplicateCount} duplicates found. Please remove them.`)
+    })
+  })
 })