add tests to @turf/destination (#682)

* add tests to show destination results #681

* passed units to distance() in test.js

packages/turf-destination/package.json

@@ -32,6 +32,8 @@
   "homepage": "https://github.com/Turfjs/turf",
   "devDependencies": {
     "@turf/distance": "^4.1.0",
+    "@turf/truncate": "^4.1.0",
+    "@turf/great-circle": "^4.1.0",
     "benchmark": "^1.0.0",
     "tape": "^3.5.0"
   },

packages/turf-destination/test.js

@@ -3,29 +3,46 @@ const load = require('load-json-file');
 const fs = require('fs');
 const path = require('path');
 const test = require('tape');
+const distance = require('@turf/distance');
+const truncate = require('@turf/truncate');
+const {featureCollection} = require('@turf/helpers');
+const greatCircle = require('@turf/great-circle');
 const destination = require('./');
 
 const directories = {
     in: path.join(__dirname, 'test', 'in') + path.sep,
     out: path.join(__dirname, 'test', 'out') + path.sep
 };
 
+const round = (num, decimals) => {
+    const factor = Math.pow(10, decimals);
+    return Math.round(num * factor) / factor;
+}
+
 const fixtures = fs.readdirSync(directories.in).map(filename => {
     return {
         filename,
         name: path.parse(filename).name,
-        geojson: load.sync(directories.in + filename)
+        inputPoint: load.sync(directories.in + filename)
     };
 });
 
 test('turf-destination', t => {
-    for (const {filename, name, geojson}  of fixtures) {
-        const dist = 100;
-        const bear = 180;
-        const results = destination(geojson, dist, bear, 'kilometers');
+    for (const {filename, name, inputPoint}  of fixtures) {
+        let {bearing, dist, units} = inputPoint.properties || {};
+        bearing = (bearing !== undefined) ? bearing : 180;
+        dist = (dist !== undefined) ? dist : 100;
+        units = units || 'kilometers';
+
+        const resultPoint = destination(inputPoint, dist, bearing, units);
+        const line = truncate(greatCircle(inputPoint, resultPoint, {"stroke": "#F00", "stroke-width": 4}));
+        inputPoint.properties['marker-color'] = '#F00';
+        const result = featureCollection([line, inputPoint, resultPoint]);
+        const d = distance(inputPoint, resultPoint, units);
 
-        if (process.env.REGEN) write.sync(directories.out + filename, results);
-        t.deepEqual(results, load.sync(directories.out + filename), name);
+        if (process.env.REGEN) write.sync(directories.out + filename, result);
+        t.deepEqual(result, load.sync(directories.out + filename), name);
+        t.equals(dist, round(d, 9), 'distance');
     }
     t.end();
 });

packages/turf-destination/test/in/point-0.geojson

@@ -0,0 +1,13 @@
+{
+  "type": "Feature",
+  "properties": {
+    "bearing": 0
+  },
+  "geometry": {
+    "type": "Point",
+    "coordinates": [
+      -75,
+      38.10096062273525
+    ]
+  }
+}

packages/turf-destination/test/in/point-90.geojson

@@ -0,0 +1,13 @@
+{
+  "type": "Feature",
+  "properties": {
+    "bearing": 90
+  },
+  "geometry": {
+    "type": "Point",
+    "coordinates": [
+      -75,
+      39
+    ]
+  }
+}

packages/turf-destination/test/in/point-way-far-away.geojson

@@ -0,0 +1,15 @@
+{
+  "type": "Feature",
+  "properties": {
+    "bearing": 90,
+    "dist": 5000,
+    "units": "miles"
+  },
+  "geometry": {
+    "type": "Point",
+    "coordinates": [
+      -75,
+      39
+    ]
+  }
+}