Move JsonMapper to spring-cloud-function-context

...in case it is needed elsewhere (see gh-151)

spring-cloud-function-context/src/test/java/org/springframework/cloud/function/util/JsonMapperTests.java

@@ -0,0 +1,109 @@
+/*
+ * 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.util;
+
+import java.util.Arrays;
+import java.util.List;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.gson.Gson;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameters;
+
+import org.springframework.cloud.function.json.GsonMapper;
+import org.springframework.cloud.function.json.JacksonMapper;
+import org.springframework.cloud.function.json.JsonMapper;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Dave Syer
+ *
+ */
+@RunWith(Parameterized.class)
+public class JsonMapperTests {
+
+	private JsonMapper mapper;
+
+	@Parameters
+	public static List<Object[]> params() {
+		return Arrays.asList(new Object[] { new GsonMapper(new Gson()) },
+				new Object[] { new JacksonMapper(new ObjectMapper()) });
+	}
+
+	public JsonMapperTests(JsonMapper mapper) {
+		this.mapper = mapper;
+	}
+
+	@Test
+	public void vanillaArray() {
+		String json = "[{\"value\":\"foo\"},{\"value\":\"foo\"}]";
+		List<Foo> list = mapper.toList(json,
+				Foo.class);
+		assertThat(list).hasSize(2);
+		assertThat(list.get(0).getValue()).isEqualTo("foo");
+		assertThat(mapper.toString(list)).isEqualTo(json);
+	}
+
+	@Test
+	public void intArray() {
+		List<Integer> list = mapper.toList("[123,456]", Integer.class);
+		assertThat(list).hasSize(2);
+		assertThat(list.get(0)).isEqualTo(123);
+	}
+
+	@Test
+	public void emptyArray() {
+		List<Foo> list = mapper.toList("[]", Foo.class);
+		assertThat(list).hasSize(0);
+	}
+
+	@Test
+	public void vanillaObject() {
+		String json = "{\"value\":\"foo\"}";
+		Foo foo = mapper.toSingle(json, Foo.class);
+		assertThat(foo.getValue()).isEqualTo("foo");
+		assertThat(mapper.toString(foo)).isEqualTo(json);
+	}
+
+	@Test
+	public void intValue() {
+		int foo = mapper.toSingle("123", Integer.class);
+		assertThat(foo).isEqualTo(123);
+	}
+
+	@Test
+	public void empty() {
+		Foo foo = mapper.toSingle("{}", Foo.class);
+		assertThat(foo.getValue()).isNull();
+	}
+
+	public static class Foo {
+		private String value;
+
+		public String getValue() {
+			return value;
+		}
+
+		public void setValue(String value) {
+			this.value = value;
+		}
+
+	}
+}