diff --git a/spring-core/src/test/java/org/springframework/core/io/ResourceTests.java b/spring-core/src/test/java/org/springframework/core/io/ResourceTests.java
index b80e5803f1e..ba18f3f2bd4 100644
--- a/spring-core/src/test/java/org/springframework/core/io/ResourceTests.java
+++ b/spring-core/src/test/java/org/springframework/core/io/ResourceTests.java
@@ -21,6 +21,8 @@ import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
 import java.nio.ByteBuffer;
 import java.nio.channels.ReadableByteChannel;
 import java.nio.file.Path;
@@ -29,12 +31,11 @@ import java.util.HashSet;
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.tests.EnabledForTestGroups;
 import org.springframework.util.FileCopyUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.springframework.tests.TestGroup.CI;
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
 
 /**
  * Unit tests for various {@link Resource} implementations.
@@ -220,12 +221,28 @@ class ResourceTests {
 	}
 
 	@Test
-	@EnabledForTestGroups(CI)
-	void testNonFileResourceExists() throws Exception {
-		Resource resource = new UrlResource("https://spring.io/");
+	void nonFileResourceExists() throws Exception {
+		URL url = new URL("https://spring.io/");
+
+		// Abort if spring.io is not reachable.
+		assumeTrue(urlIsReachable(url));
+
+		Resource resource = new UrlResource(url);
 		assertThat(resource.exists()).isTrue();
 	}
 
+	private boolean urlIsReachable(URL url) {
+		try {
+			HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+			connection.setRequestMethod("HEAD");
+			connection.setReadTimeout(5_000);
+			return connection.getResponseCode() == HttpURLConnection.HTTP_OK;
+		}
+		catch (Exception ex) {
+			return false;
+		}
+	}
+
 	@Test
 	void abstractResourceExceptions() throws Exception {
 		final String name = "test-resource";
diff --git a/spring-core/src/test/java/org/springframework/tests/AssumeTests.java b/spring-core/src/test/java/org/springframework/tests/AssumeTests.java
index 1accee1ef82..f077ffe6170 100644
--- a/spring-core/src/test/java/org/springframework/tests/AssumeTests.java
+++ b/spring-core/src/test/java/org/springframework/tests/AssumeTests.java
@@ -29,7 +29,6 @@ import static org.assertj.core.api.Assertions.assertThatCode;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.springframework.tests.Assume.TEST_GROUPS_SYSTEM_PROPERTY;
-import static org.springframework.tests.TestGroup.CI;
 import static org.springframework.tests.TestGroup.LONG_RUNNING;
 import static org.springframework.tests.TestGroup.PERFORMANCE;
 
@@ -70,7 +69,7 @@ class AssumeTests {
 	@Test
 	@SuppressWarnings("deprecation")
 	void assumeGroupWithNoMatchingActiveTestGroup() {
-		setTestGroups(PERFORMANCE, CI);
+		setTestGroups(PERFORMANCE);
 		assertThatExceptionOfType(TestAbortedException.class).isThrownBy(() -> Assume.group(LONG_RUNNING));
 	}
 
@@ -99,7 +98,7 @@ class AssumeTests {
 		//
 		// java.lang.IllegalStateException: Failed to parse 'testGroups' system property:
 		// Unable to find test group 'bogus' when parsing testGroups value: 'all-bogus'.
-		// Available groups include: [LONG_RUNNING,PERFORMANCE,CI]
+		// Available groups include: [LONG_RUNNING,PERFORMANCE]
 
 		setTestGroups(testGroups);
 		assertThatIllegalStateException()
@@ -109,7 +108,7 @@ class AssumeTests {
 			.satisfies(ex ->
 				assertThat(ex.getCause().getMessage()).isEqualTo(
 					"Unable to find test group 'bogus' when parsing testGroups value: '" + testGroups +
-					"'. Available groups include: [LONG_RUNNING,PERFORMANCE,CI]"));
+					"'. Available groups include: [LONG_RUNNING,PERFORMANCE]"));
 	}
 
 	private void setTestGroups(TestGroup... testGroups) {
diff --git a/spring-core/src/test/java/org/springframework/tests/TestGroup.java b/spring-core/src/test/java/org/springframework/tests/TestGroup.java
index c597c859e8d..f04c47bc182 100644
--- a/spring-core/src/test/java/org/springframework/tests/TestGroup.java
+++ b/spring-core/src/test/java/org/springframework/tests/TestGroup.java
@@ -49,12 +49,7 @@ public enum TestGroup {
 	 * {@code StopWatch}, etc. should be considered a candidate as their successful
 	 * execution is likely to be based on events occurring within a given time window.
 	 */
-	PERFORMANCE,
-
-	/**
-	 * Tests that should only be run on the continuous integration server.
-	 */
-	CI;
+	PERFORMANCE;
 
 
 	/**
@@ -82,6 +77,7 @@ public enum TestGroup {
 					"' system property: " + ex.getMessage(), ex);
 		}
 	}
+
 	/**
 	 * Parse the specified comma separated string of groups.
 	 * @param value the comma separated string of groups
diff --git a/spring-core/src/test/java/org/springframework/tests/TestGroupTests.java b/spring-core/src/test/java/org/springframework/tests/TestGroupTests.java
index 152a63041a4..5377c4b5f74 100644
--- a/spring-core/src/test/java/org/springframework/tests/TestGroupTests.java
+++ b/spring-core/src/test/java/org/springframework/tests/TestGroupTests.java
@@ -64,7 +64,7 @@ class TestGroupTests {
 			.isThrownBy(() -> TestGroup.parse("performance, missing"))
 			.withMessageContaining("Unable to find test group 'missing' when parsing " +
 					"testGroups value: 'performance, missing'. Available groups include: " +
-					"[LONG_RUNNING,PERFORMANCE,CI]");
+					"[LONG_RUNNING,PERFORMANCE]");
 	}
 
 	@Test
@@ -85,7 +85,7 @@ class TestGroupTests {
 			.isThrownBy(() -> TestGroup.parse("all-missing"))
 			.withMessageContaining("Unable to find test group 'missing' when parsing " +
 					"testGroups value: 'all-missing'. Available groups include: " +
-					"[LONG_RUNNING,PERFORMANCE,CI]");
+					"[LONG_RUNNING,PERFORMANCE]");
 	}
 
 }