diff --git a/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/DisabledConfigResourceClientTests.java b/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/DisabledConfigResourceClientTests.java
index ebeaf3e..2587595 100644
--- a/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/DisabledConfigResourceClientTests.java
+++ b/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/DisabledConfigResourceClientTests.java
@@ -16,21 +16,18 @@
 
 package io.pivotal.spring.cloud.config.client;
 
-import org.junit.Assert;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
+import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.context.annotation.Import;
 import org.springframework.core.env.Environment;
 import org.springframework.test.context.ActiveProfiles;
-import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
 
 /**
  * @author Daniel Lavoie
  */
-@RunWith(SpringRunner.class)
 @Import(ConfigResourceClientAutoConfiguration.class)
 @SpringBootTest(classes = DisabledConfigResourceClientTests.class)
 @ActiveProfiles("integration-test")
@@ -44,8 +41,8 @@ public class DisabledConfigResourceClientTests {
 
 	@Test
 	public void configClientBeanShouldNotBeInjected() {
-		Assert.assertNotNull("Spring container is not initialized.", environment);
-		Assert.assertNull(plainTextConfigClient);
+		assertThat(environment).isNotNull();
+		assertThat(plainTextConfigClient).isNull();
 	}
 
 }
diff --git a/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/OAuth2ConfigResourceClientTest.java b/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/OAuth2ConfigResourceClientTest.java
index 3e543db..5da3d9a 100644
--- a/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/OAuth2ConfigResourceClientTest.java
+++ b/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/OAuth2ConfigResourceClientTest.java
@@ -21,25 +21,23 @@
 import java.io.InputStreamReader;
 import java.util.stream.Collectors;
 
-import org.junit.Assert;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.web.server.LocalServerPort;
 import org.springframework.cloud.config.client.ConfigClientProperties;
 import org.springframework.core.io.Resource;
 import org.springframework.mock.env.MockEnvironment;
-import org.springframework.test.context.junit4.SpringRunner;
 import org.springframework.web.client.HttpClientErrorException;
 import org.springframework.web.client.RestTemplate;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
 /**
  * @author Daniel Lavoie
  * @author Dylan Roberts
  */
-@RunWith(SpringRunner.class)
 @SpringBootTest(classes = ConfigServerTestApplication.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT,
 		properties = { "spring.profiles.active=plaintext,native", "spring.cloud.config.enabled=true",
 				"eureka.client.enabled=false", "spring.config.import=optional:configserver:" })
@@ -72,8 +70,8 @@ public class OAuth2ConfigResourceClientTest {
 
 	private ConfigResourceClient configClient;
 
-	@Before
-	public void setUp() {
+	@BeforeEach
+	public void setup() {
 		configClientProperties = new ConfigClientProperties(new MockEnvironment());
 		configClientProperties.setName("app");
 		configClientProperties.setProfile(null);
@@ -83,32 +81,35 @@ public void setUp() {
 
 	@Test
 	public void shouldFindSimplePlainFile() {
-		Assert.assertEquals(NGINX_CONFIG, read(configClient.getPlainTextResource(null, "master", "nginx.conf")));
+		assertThat(read(configClient.getPlainTextResource(null, "master", "nginx.conf"))).isEqualTo(NGINX_CONFIG);
 
-		Assert.assertEquals(DEV_NGINX_CONFIG, read(configClient.getPlainTextResource("dev", "master", "nginx.conf")));
+		assertThat(read(configClient.getPlainTextResource("dev", "master", "nginx.conf"))).isEqualTo(DEV_NGINX_CONFIG);
 
 		configClientProperties.setProfile("test");
-		Assert.assertEquals(TEST_NGINX_CONFIG, read(configClient.getPlainTextResource(null, "master", "nginx.conf")));
+		assertThat(read(configClient.getPlainTextResource(null, "master", "nginx.conf"))).isEqualTo(TEST_NGINX_CONFIG);
 	}
 
-	@Test(expected = HttpClientErrorException.class)
+	@Test
 	public void missingConfigFileShouldReturnHttpError() {
-		configClient.getPlainTextResource(null, "master", "missing-config.xml");
+		assertThatThrownBy(() -> configClient.getPlainTextResource(null, "master", "missing-config.xml"))
+			.isInstanceOf(HttpClientErrorException.class);
 	}
 
-	@Test(expected = IllegalArgumentException.class)
+	@Test
 	public void missingApplicationNameShouldCrash() {
 		configClientProperties.setName("");
-		configClient.getPlainTextResource(null, "master", "nginx.conf");
+		assertThatThrownBy(() -> configClient.getPlainTextResource(null, "master", "nginx.conf"))
+			.isInstanceOf(IllegalArgumentException.class);
 	}
 
-	@Test(expected = IllegalArgumentException.class)
+	@Test
 	public void missingConfigServerUrlShouldCrash() {
 		configClientProperties.setUri(new String[] { "" });
-		configClient.getPlainTextResource(null, "master", "nginx.conf");
+		assertThatThrownBy(() -> configClient.getPlainTextResource(null, "master", "nginx.conf"))
+			.isInstanceOf(IllegalArgumentException.class);
 	}
 
-	public String read(Resource resource) {
+	private String read(Resource resource) {
 		try (BufferedReader buffer = new BufferedReader(new InputStreamReader(resource.getInputStream()))) {
 			return buffer.lines().collect(Collectors.joining("\n"));
 		}
diff --git a/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/PropertyMaskingEnvironmentPostProcessorTest.java b/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/PropertyMaskingEnvironmentPostProcessorTest.java
index 353b875..76d69df 100644
--- a/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/PropertyMaskingEnvironmentPostProcessorTest.java
+++ b/spring-cloud-services-config-client-autoconfigure/src/test/java/io/pivotal/spring/cloud/config/client/PropertyMaskingEnvironmentPostProcessorTest.java
@@ -18,9 +18,7 @@
 import java.util.HashMap;
 import java.util.Map;
 
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
+import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.test.context.SpringBootContextLoader;
@@ -32,7 +30,6 @@
 import org.springframework.core.env.StandardEnvironment;
 import org.springframework.test.context.ActiveProfiles;
 import org.springframework.test.context.ContextConfiguration;
-import org.springframework.test.context.junit4.SpringRunner;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -80,7 +77,6 @@ protected ConfigurableEnvironment getEnvironment() {
 
 	}
 
-	@RunWith(SpringRunner.class)
 	@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
 	@ActiveProfiles({ "integration-test", "native" })
 	@ContextConfiguration(classes = TestVaultApplication.class, loader = VaultPropertySourceContextLoader.class)