diff --git a/pom.xml b/pom.xml
index 3d037b85..5007f1a0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -141,7 +141,7 @@ SOFTWARE.
     <dependency>
       <groupId>com.yegor256</groupId>
       <artifactId>jping</artifactId>
-      <version>0.0.4</version>
+      <version>0.0.3</version>
       <scope>test</scope>
     </dependency>
     <dependency>
diff --git a/src/test/java/org/eolang/lints/LintByXslTest.java b/src/test/java/org/eolang/lints/LintByXslTest.java
index 5540a139..f012357b 100644
--- a/src/test/java/org/eolang/lints/LintByXslTest.java
+++ b/src/test/java/org/eolang/lints/LintByXslTest.java
@@ -25,6 +25,7 @@
 
 import com.jcabi.xml.XML;
 import com.jcabi.xml.XMLDocument;
+import com.yegor256.MayBeSlow;
 import com.yegor256.WeAreOnline;
 import com.yegor256.xsline.Shift;
 import com.yegor256.xsline.StClasspath;
@@ -69,8 +70,8 @@ void lintsOneFile() throws IOException {
     }
 
     @ParameterizedTest
+    @ExtendWith(MayBeSlow.class)
     @ExtendWith(WeAreOnline.class)
-    @ExtendWith(M)
     @ClasspathSource(value = "org/eolang/lints/eo-packs/", glob = "**.yaml")
     void testsAllLintsByEo(final String pack) throws IOException {
         final CheckPack check = new CheckPack(pack);
@@ -86,6 +87,7 @@ void testsAllLintsByEo(final String pack) throws IOException {
 
     @ParameterizedTest
     @SuppressWarnings("unchecked")
+    @ExtendWith(MayBeSlow.class)
     @ExtendWith(WeAreOnline.class)
     @ClasspathSource(value = "org/eolang/lints/xmir-packs/", glob = "**.yaml")
     void testsAllLintsByXmir(final String pack) {
diff --git a/src/test/resources/log4j.properties b/src/test/resources/log4j.properties
index 3675ee28..e8d30fb8 100644
--- a/src/test/resources/log4j.properties
+++ b/src/test/resources/log4j.properties
@@ -27,3 +27,4 @@ log4j.appender.CONSOLE.layout=com.jcabi.log.MulticolorLayout
 log4j.appender.CONSOLE.layout.ConversionPattern=%d{HH:mm:ss} [%p] %c: %m%n
 
 log4j.logger.org.eolang.parser.CheckPack=INFO
+log4j.logger.com.yegor256.MayBeSlow=INFO