add(core) enforceWebGL2 tests

Signed-off-by: Chris Gervang <chris@gervang.com>

modules/core/src/adapter/luma.ts

@@ -156,6 +156,7 @@ export class luma {
       // Reset the original getContext function
       prototype.getContext = prototype.originalGetContext;
       prototype.originalGetContext = undefined;
+      return;
     }
 
     // Store the original getContext function

modules/core/test/adapter/luma.spec.ts

@@ -30,3 +30,51 @@ test('luma#registerDevices', async t => {
   t.equal(device.info.renderer, 'none', 'info.renderer ok');
   t.end();
 });
+
+// To suppress @typescript-eslint/unbound-method
+interface TestHTMLCanvasElement {
+  getContext: (contextId: any, options?: unknown) => string;
+  originalGetContext?: (contextId: any, options?: unknown) => unknown;
+}
+
+test('luma#enforceWebGL2', async t => {
+  const prototype = HTMLCanvasElement.prototype as unknown as TestHTMLCanvasElement;
+
+  // Setup mock getContext
+  const originalGetContext = prototype.getContext;
+  prototype.getContext = function (contextId: any, options?: unknown) {
+    return contextId;
+  };
+  // Revert mock test completes.
+  t.teardown(() => {
+    prototype.getContext = originalGetContext;
+  });
+
+  t.equal(prototype.getContext('webgl'), 'webgl', 'getContext webgl ok');
+  t.equal(
+    prototype.getContext('experimental-webgl'),
+    'experimental-webgl',
+    'getContext experimental-webgl ok'
+  );
+  t.equal(prototype.getContext('webgl2'), 'webgl2', 'getContext webgl2 ok');
+
+  luma.enforceWebGL2();
+
+  t.true(prototype.originalGetContext, 'originalGetContext ok');
+  t.equal(prototype.getContext('webgl'), 'webgl2', 'getContext enforce webgl2 ok');
+  t.equal(prototype.getContext('experimental-webgl'), 'webgl2', 'getContext enforce webgl2 ok');
+  t.equal(prototype.getContext('webgl2'), 'webgl2', 'getContext webgl2 ok');
+
+  luma.enforceWebGL2(false);
+
+  t.false(prototype.originalGetContext, 'originalGetContext ok');
+  t.equal(prototype.getContext('webgl'), 'webgl', 'getContext revert webgl ok');
+  t.equal(
+    prototype.getContext('experimental-webgl'),
+    'experimental-webgl',
+    'getContext revert experimental-webgl ok'
+  );
+  t.equal(prototype.getContext('webgl2'), 'webgl2', 'getContext webgl2 ok');
+
+  t.end();
+});