Allow reading and writing empty designs (#7749).

Change-Id: Id66201d040d07f0e0d731418624c9b702b2d0d3b

2 files changed, 136 insertions, 0 deletions

diff --git a/server/tests/src/com/vaadin/tests/server/component/TestReadEmptyDesign.java b/server/tests/src/com/vaadin/tests/server/component/TestReadEmptyDesign.java
new file mode 100644
index 0000000000..ecd303b678
--- /dev/null
+++ b/server/tests/src/com/vaadin/tests/server/component/TestReadEmptyDesign.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2000-2014 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.tests.server.component;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+
+import junit.framework.TestCase;
+
+import org.jsoup.nodes.Document;
+import org.jsoup.nodes.DocumentType;
+import org.jsoup.nodes.Element;
+
+import com.vaadin.ui.Component;
+import com.vaadin.ui.VerticalLayout;
+import com.vaadin.ui.declarative.Design;
+import com.vaadin.ui.declarative.DesignContext;
+import com.vaadin.ui.declarative.DesignException;
+
+/**
+ * Test cases for checking that reading a design with no elements in the html
+ * body produces null as the root component.
+ */
+public class TestReadEmptyDesign extends TestCase {
+    InputStream is;
+
+    @Override
+    protected void setUp() throws Exception {
+        super.setUp();
+        String html = createDesign().toString();
+        is = new ByteArrayInputStream(html.getBytes());
+    }
+
+    public void testReadComponent() {
+        Component root = Design.read(is);
+        assertNull("The root component should be null.", root);
+    }
+
+    public void testReadContext() {
+        DesignContext ctx = Design.read(is, null);
+        assertNotNull("The design context should not be null.", ctx);
+        assertNull("The root component should be null.", ctx.getRootComponent());
+    }
+
+    public void testReadContextWithRootParameter() {
+        try {
+            Component rootComponent = new VerticalLayout();
+            DesignContext ctx = Design.read(is, rootComponent);
+            fail("Reading a design with no elements should fail when a non-null root Component is specified.");
+        } catch (DesignException e) {
+            // This is the expected outcome, nothing to do.
+        }
+    }
+
+    private Document createDesign() {
+        Document doc = new Document("");
+        DocumentType docType = new DocumentType("html", "", "", "");
+        doc.appendChild(docType);
+        Element html = doc.createElement("html");
+        doc.appendChild(html);
+        html.appendChild(doc.createElement("head"));
+        html.appendChild(doc.createElement("body"));
+        return doc;
+    }
+}
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diff --git a/server/tests/src/com/vaadin/tests/server/component/TestWriteEmptyDesign.java b/server/tests/src/com/vaadin/tests/server/component/TestWriteEmptyDesign.java
new file mode 100644
index 0000000000..b50915f1fd
--- /dev/null
+++ b/server/tests/src/com/vaadin/tests/server/component/TestWriteEmptyDesign.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2000-2014 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.tests.server.component;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+
+import junit.framework.TestCase;
+
+import org.jsoup.Jsoup;
+import org.jsoup.nodes.Document;
+import org.jsoup.nodes.Element;
+
+import com.vaadin.ui.Component;
+import com.vaadin.ui.declarative.Design;
+import com.vaadin.ui.declarative.DesignContext;
+
+/**
+ * Test cases for checking that writing a component hierarchy with null root
+ * produces an html document that has no elements in the html body.
+ */
+public class TestWriteEmptyDesign extends TestCase {
+
+    public void testWriteComponent() throws IOException {
+        OutputStream os = new ByteArrayOutputStream();
+        Design.write((Component) null, os);
+        checkHtml(os.toString());
+    }
+
+    public void testWriteContext() throws IOException {
+        OutputStream os = new ByteArrayOutputStream();
+        DesignContext ctx = new DesignContext();
+        ctx.setRootComponent(null);
+        Design.write(ctx, os);
+        checkHtml(os.toString());
+    }
+
+    private void checkHtml(String html) {
+        Document doc = Jsoup.parse(html);
+        Element body = doc.body();
+        assertEquals("There should be no elements in the html body.", "",
+                body.html());
+    }
+}
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