NoArgConstructor for InstanceCredentials, so it can be loaded as

ConfigurationProperties

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/server/web/client/BasicAuthHttpHeaderProvider.java

@@ -27,6 +27,7 @@
 import org.springframework.util.StringUtils;
 
 import de.codecentric.boot.admin.server.domain.entities.Instance;
+import lombok.NoArgsConstructor;
 
 /**
  * Provides Basic Auth headers for the {@link Instance} using the metadata for "user.name"
@@ -103,6 +104,7 @@ protected String encode(String username, String password) {
 	}
 
 	@lombok.Data(staticConstructor = "of")
+	@NoArgsConstructor
 	public static class InstanceCredentials {
 
 		/**

spring-boot-admin-server/src/test/java/de/codecentric/boot/admin/server/config/AdminServerPropertiesTest.java

@@ -0,0 +1,32 @@
+package de.codecentric.boot.admin.server.config;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+@ExtendWith(SpringExtension.class)
+@EnableConfigurationProperties(value = AdminServerProperties.class)
+@TestPropertySource("classpath:server-config-test.properties")
+public class AdminServerPropertiesTest {
+
+    @Autowired
+    private AdminServerProperties serverConfig;
+
+    @Test
+    void testLoadConfigurationProperties() {
+
+    	assertEquals("/admin", serverConfig.getContextPath());
+
+    	assertEquals("admin", serverConfig.getInstanceAuth().getDefaultUserName());
+    	assertEquals("topsecret", serverConfig.getInstanceAuth().getDefaultPassword());
+
+    	assertEquals("me", serverConfig.getInstanceAuth().getServiceMap().get("my-service").getUserName());
+    	assertEquals("secret", serverConfig.getInstanceAuth().getServiceMap().get("my-service").getUserPassword());
+    }
+
+}

spring-boot-admin-server/src/test/resources/server-config-test.properties

@@ -0,0 +1,7 @@
+spring.boot.admin.contextPath=/admin
+
+spring.boot.admin.instance-auth.default-user-name=admin
+spring.boot.admin.instance-auth.default-password=topsecret
+
+spring.boot.admin.instance-auth.service-map.my-service.userName=me
+spring.boot.admin.instance-auth.service-map.my-service.userPassword=secret