Throw on non-numeric opacity values

test/spec/ol/layer/layer.test.js

@@ -112,6 +112,19 @@ describe('ol.layer.Layer', function() {
       layer.dispose();
     });
 
+    it('throws on non-numeric opacity', function() {
+      function create() {
+        new Layer({
+          source: new Source({
+            projection: 'EPSG:4326'
+          }),
+          opacity: 'foo'
+        });
+      }
+
+      expect(create).to.throwException();
+    });
+
     it('accepts a custom render function', function() {
       let called = false;
       const layer = new Layer({
@@ -511,6 +524,13 @@ describe('ol.layer.Layer', function() {
       expect(layer.getOpacity()).to.be(0.3);
     });
 
+    it('throws on types other than number', function() {
+      function set() {
+        layer.setOpacity('foo');
+      }
+      expect(set).to.throwException();
+    });
+
     it('triggers a change event', function() {
       const listener = sinon.spy();
       layer.on('propertychange', listener);