management.server.port should be 0 when local.server.port has

the same value and `management.server.port` has been defined
in the different PropertySource

gh-16102

Author: nosan

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/web/SpringBootTestRandomPortEnvironmentPostProcessor.java

@@ -57,7 +57,7 @@ public void postProcessEnvironment(ConfigurableEnvironment environment,
 		}
 		Integer serverPort = getPropertyAsInteger(environment, SERVER_PORT_PROPERTY,
 				8080);
-		if (!managementPort.equals(serverPort)) {
+		if (!managementPort.equals(serverPort) || managementPort == 0) {
 			source.getSource().put(MANAGEMENT_PORT_PROPERTY, "0");
 		}
 		else {

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/web/SpringBootTestRandomPortEnvironmentPostProcessorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -58,6 +58,17 @@ public void postProcessWhenServerAndManagementPortIsZeroInTestPropertySource() {
 		assertThat(this.environment.getProperty("management.server.port")).isEqualTo("0");
 	}
 
+	@Test
+	public void postProcessWhenServerPortAndManagementPortIsZeroInDifferentPropertySources() {
+		addTestPropertySource("0", null);
+		Map<String, Object> source = new HashMap<>();
+		source.put("management.server.port", "0");
+		this.propertySources.addLast(new MapPropertySource("other", source));
+		this.postProcessor.postProcessEnvironment(this.environment, null);
+		assertThat(this.environment.getProperty("server.port")).isEqualTo("0");
+		assertThat(this.environment.getProperty("management.server.port")).isEqualTo("0");
+	}
+
 	@Test
 	public void postProcessWhenTestServerAndTestManagementPortAreNonZero() {
 		addTestPropertySource("8080", "8081");