Tighten up contract for SingleEntryFunctionRegistry

And add some tests. Fixes gh-250.

spring-cloud-function-deployer/src/test/java/org/springframework/cloud/function/deployer/SingleEntryFunctionRegistryTests.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2016-2017 the original author or authors.
+ *
+ * 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 org.springframework.cloud.function.deployer;
+
+import java.util.function.Function;
+
+import org.junit.Test;
+
+import org.springframework.cloud.function.context.FunctionRegistration;
+import org.springframework.cloud.function.context.catalog.InMemoryFunctionCatalog;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Dave Syer
+ *
+ */
+public class SingleEntryFunctionRegistryTests {
+
+	private InMemoryFunctionCatalog delegate = new InMemoryFunctionCatalog();
+
+	@Test
+	public void named() {
+		delegate.register(new FunctionRegistration<Foos>(new Foos(), "foo"));
+		SingleEntryFunctionRegistry registry = new SingleEntryFunctionRegistry(delegate,
+				"foo");
+		assertThat((Foos) registry.lookup("foo")).isInstanceOf(Function.class);
+	}
+
+	@Test
+	public void other() {
+		delegate.register(new FunctionRegistration<Foos>(new Foos(), "foo"));
+		SingleEntryFunctionRegistry registry = new SingleEntryFunctionRegistry(delegate,
+				"foo");
+		assertThat((Foos) registry.lookup("bar")).isNull();
+	}
+
+	@Test
+	public void empty() {
+		delegate.register(new FunctionRegistration<Foos>(new Foos(), ""));
+		SingleEntryFunctionRegistry registry = new SingleEntryFunctionRegistry(delegate,
+				"");
+		assertThat((Foos) registry.lookup("")).isInstanceOf(Function.class);
+	}
+
+	@Test
+	public void anonymous() {
+		delegate.register(new FunctionRegistration<Foos>(new Foos(), "bar"));
+		SingleEntryFunctionRegistry registry = new SingleEntryFunctionRegistry(delegate,
+				"foo");
+		assertThat((Foos) registry.lookup("")).isInstanceOf(Function.class);
+	}
+
+	class Foos implements Function<String, String> {
+
+		@Override
+		public String apply(String t) {
+			return t.toUpperCase();
+		}
+
+	}
+
+}