Fix bug registering component with static view.is prop but no view.file prop

src/App.ts

@@ -163,9 +163,13 @@ export abstract class AppBase<T = object> extends EventEmitter {
       this.addViews(viewSource, viewName);
       view = this.views.find(viewName);
 
-    } else if (name) {
+    } else if (viewName) {
+      // Look for a previously registered view matching the component name.
       view = this.views.find(viewName);
-
+      // If no match, register a new empty view, for backwards compatibility.
+      if (!view) {
+        view = this.views.register(viewName, '');
+      }
     } else {
       view = this.views.register(viewName, '');
     }

test/all/ComponentHarness.mocha.js

@@ -258,8 +258,6 @@ describe('ComponentHarness', function() {
     });
 
     it('gets overridden without error', function() {
-      function ConflictingClown() {}
-      ConflictingClown.view = {is: 'clown'};
       function Clown() {}
       Clown.view = {
         is: 'clown',
@@ -277,6 +275,8 @@ describe('ComponentHarness', function() {
             '</div>',
         dependencies: [Clown]
       };
+      function ConflictingClown() {}
+      ConflictingClown.view = {is: 'clown', source: '<index:>'};
       var html = new ComponentHarness(
         '<view is="box" />', Box, ConflictingClown
       ).renderHtml().html;

test/dom/components.mocha.js

@@ -0,0 +1,58 @@
+var expect = require('chai').expect;
+var pathLib = require('node:path');
+var domTestRunner = require('../../test-utils/domTestRunner');
+
+describe('components', function() {
+  var runner = domTestRunner.install();
+
+  describe('app.component registration', function() {
+    describe('passing just component class', function() {
+      describe('with static view prop', function() {
+        it('external view file', function() {
+          var harness = runner.createHarness();
+
+          function SimpleBox() {}
+          SimpleBox.view = {
+            is: 'simple-box',
+            // Static `view.file` property, defining path of view file
+            file: pathLib.resolve(__dirname, '../fixtures/simple-box')
+          };
+          harness.app.component(SimpleBox);
+
+          harness.setup('<view is="simple-box"/>');
+          expect(harness.renderHtml().html).to.equal('<div class="simple-box"></div>');
+        });
+
+        it('inlined view.source', function() {
+          var harness = runner.createHarness();
+
+          function SimpleBox() {}
+          SimpleBox.view = {
+            is: 'simple-box',
+            source: '<index:><div>Inlined source</div>'
+          };
+          harness.app.component(SimpleBox);
+
+          harness.setup('<view is="simple-box"/>');
+          expect(harness.renderHtml().html).to.equal('<div>Inlined source</div>');
+        });
+
+        it('inferred view file from view name', function() {
+          var harness = runner.createHarness();
+
+          // Pre-load view with same name as the component's static `view.is`
+          harness.app.loadViews(pathLib.resolve(__dirname, '../fixtures/simple-box'), 'simple-box');
+
+          function SimpleBox() {}
+          SimpleBox.view = {
+            is: 'simple-box'
+          };
+          harness.app.component(SimpleBox);
+
+          harness.setup('<view is="simple-box"/>');
+          expect(harness.renderHtml().html).to.equal('<div class="simple-box"></div>');
+        });
+      });
+    });
+  });
+});