Add node tests

test/node/ol/geom/flat/interpolate.test.js

@@ -0,0 +1,68 @@
+import expect from '../../../expect.js';
+import {interpolatePoint} from '../../../../../src/ol/geom/flat/interpolate.js';
+
+describe('ol/geom/flat/interpolate.js', function () {
+  describe('interpolatePoint', function () {
+    it('returns the expected value for single points', function () {
+      const flatCoordinates = [0, 1];
+      const point = interpolatePoint(flatCoordinates, 0, 2, 2, 0.5);
+      expect(point).to.eql([0, 1]);
+    });
+
+    it('returns the expected value for simple line segments', function () {
+      const flatCoordinates = [0, 1, 2, 3];
+      const point = interpolatePoint(flatCoordinates, 0, 4, 2, 0.5);
+      expect(point).to.eql([1, 2]);
+    });
+
+    it(
+      'returns the expected value when the mid point is an existing ' +
+        'coordinate',
+      function () {
+        const flatCoordinates = [0, 1, 2, 3, 4, 5];
+        const point = interpolatePoint(flatCoordinates, 0, 6, 2, 0.5);
+        expect(point).to.eql([2, 3]);
+      }
+    );
+
+    it('also when vertices are repeated', function () {
+      const flatCoordinates = [0, 1, 2, 3, 2, 3, 4, 5];
+      const point = interpolatePoint(flatCoordinates, 0, 8, 2, 0.5);
+      expect(point).to.eql([2, 3]);
+    });
+
+    it(
+      'returns the expected value when the midpoint falls halfway between ' +
+        'two existing coordinates',
+      function () {
+        const flatCoordinates = [0, 1, 2, 3, 4, 5, 6, 7];
+        const point = interpolatePoint(flatCoordinates, 0, 8, 2, 0.5);
+        expect(point).to.eql([3, 4]);
+      }
+    );
+
+    it('also when vertices are repeated', function () {
+      const flatCoordinates = [0, 1, 2, 3, 2, 3, 4, 5, 6, 7];
+      const point = interpolatePoint(flatCoordinates, 0, 10, 2, 0.5);
+      expect(point).to.eql([3, 4]);
+    });
+
+    it('returns the expected value when the coordinates are not evenly spaced', function () {
+      const flatCoordinates = [0, 1, 2, 3, 6, 7];
+      const point = interpolatePoint(flatCoordinates, 0, 6, 2, 0.5);
+      expect(point).to.eql([3, 4]);
+    });
+
+    it('also when vertices are repeated', function () {
+      const flatCoordinates = [0, 1, 2, 3, 2, 3, 6, 7];
+      const point = interpolatePoint(flatCoordinates, 0, 8, 2, 0.5);
+      expect(point).to.eql([3, 4]);
+    });
+
+    it('returns the expected value when using opt_dest', function () {
+      const flatCoordinates = [0, 1, 2, 3, 6, 7];
+      const point = interpolatePoint(flatCoordinates, 0, 6, 2, 0.5, [0, 0]);
+      expect(point).to.eql([3, 4]);
+    });
+  });
+});