Fix internal port check when other ports are opened as well on the target container

core/src/main/java/org/testcontainers/containers/ExecInContainerPattern.java

@@ -66,10 +66,6 @@ public Container.ExecResult execInContainer(InspectContainerResponse containerIn
 
         DockerClient dockerClient = DockerClientFactory.instance().client();
 
-        dockerClient
-            .execCreateCmd(containerId)
-            .withCmd(command);
-
         log.debug("{}: Running \"exec\" command: {}", containerName, String.join(" ", command));
         final ExecCreateCmdResponse execCreateCmdResponse = dockerClient.execCreateCmd(containerId)
             .withAttachStdout(true).withAttachStderr(true).withCmd(command).exec();

core/src/main/java/org/testcontainers/containers/wait/internal/InternalCommandPortListeningCheck.java

@@ -29,7 +29,7 @@ public Boolean call() {
         for (int internalPort : internalPorts) {
             command += " && ";
             command += " (";
-            command += format("cat /proc/net/tcp* | awk '{print $2}' | grep -i :%x", internalPort);
+            command += format("cat /proc/net/tcp* | awk '{print $2}' | grep -i ':0*%x'", internalPort);
             command += " || ";
             command += format("nc -vz -w 1 localhost %d", internalPort);
             command += " || ";

core/src/test/java/org/testcontainers/containers/wait/internal/InternalCommandPortListeningCheckTest.java

@@ -3,23 +3,47 @@
 import com.google.common.collect.ImmutableSet;
 import org.junit.Rule;
 import org.junit.Test;
-import org.testcontainers.containers.BindMode;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.rnorth.ducttape.TimeoutException;
+import org.rnorth.ducttape.unreliables.Unreliables;
 import org.testcontainers.containers.GenericContainer;
+import org.testcontainers.images.builder.ImageFromDockerfile;
 
+import java.util.concurrent.TimeUnit;
+
+import static java.util.Arrays.asList;
 import static org.rnorth.visibleassertions.VisibleAssertions.assertFalse;
 import static org.rnorth.visibleassertions.VisibleAssertions.assertTrue;
 
+@RunWith(Parameterized.class)
 public class InternalCommandPortListeningCheckTest {
 
-    // Linking a custom configuration into the container so that nginx is listening on port 8080. This is necessary to prove
-    // that the command formatting uses the correct casing for hexadecimal numbers (i.e. 1F90 and not 1f90).
+    @Parameterized.Parameters(name = "{index} - {0}")
+    public static Iterable<Object[]> data() {
+        return asList(
+            new Object[][]{
+                {"internal-port-check-dockerfile/Dockerfile-tcp"},
+                {"internal-port-check-dockerfile/Dockerfile-nc"},
+                {"internal-port-check-dockerfile/Dockerfile-bash"},
+            });
+    }
+
     @Rule
-    public GenericContainer nginx = new GenericContainer<>("nginx:1.9.4")
-            .withClasspathResourceMapping("nginx_on_8080.conf", "/etc/nginx/conf.d/default.conf", BindMode.READ_ONLY);
+    public GenericContainer container;
+
+    public InternalCommandPortListeningCheckTest(String dockerfile) {
+        container = new GenericContainer(new ImageFromDockerfile()
+            .withFileFromClasspath("Dockerfile", dockerfile)
+            .withFileFromClasspath("nginx.conf", "internal-port-check-dockerfile/nginx.conf")
+        );
+    }
 
     @Test
     public void singleListening() {
-        final InternalCommandPortListeningCheck check = new InternalCommandPortListeningCheck(nginx, ImmutableSet.of(8080));
+        final InternalCommandPortListeningCheck check = new InternalCommandPortListeningCheck(container, ImmutableSet.of(8080));
+
+        Unreliables.retryUntilTrue(5, TimeUnit.SECONDS, check);
 
         final Boolean result = check.call();
 
@@ -28,10 +52,27 @@ public void singleListening() {
 
     @Test
     public void nonListening() {
-        final InternalCommandPortListeningCheck check = new InternalCommandPortListeningCheck(nginx, ImmutableSet.of(8080, 1234));
+        final InternalCommandPortListeningCheck check = new InternalCommandPortListeningCheck(container, ImmutableSet.of(8080, 1234));
+
+        try {
+            Unreliables.retryUntilTrue(5, TimeUnit.SECONDS, check);
+        } catch (TimeoutException e) {
+            // we expect it to timeout
+        }
 
         final Boolean result = check.call();
 
         assertFalse("InternalCommandPortListeningCheck detects a non-listening port among many", result);
     }
+
+    @Test
+    public void lowAndHighPortListening() {
+        final InternalCommandPortListeningCheck check = new InternalCommandPortListeningCheck(container, ImmutableSet.of(100, 8080));
+
+        Unreliables.retryUntilTrue(5, TimeUnit.SECONDS, check);
+
+        final Boolean result = check.call();
+
+        assertTrue("InternalCommandPortListeningCheck identifies a low and a high port", result);
+    }
 }

core/src/test/resources/internal-port-check-dockerfile/Dockerfile-bash

@@ -0,0 +1,11 @@
+FROM nginx:1.17-alpine
+
+RUN apk add bash
+
+# Make sure the /proc/net/tcp* check fails in this container
+RUN rm /usr/bin/awk
+
+# Make sure the nc check fails in this container
+RUN rm /usr/bin/nc
+
+ADD nginx.conf /etc/nginx/conf.d/default.conf

core/src/test/resources/internal-port-check-dockerfile/Dockerfile-nc

@@ -0,0 +1,9 @@
+FROM nginx:1.17-alpine
+
+# If this fails, you ended up using a base image with bash installed. Consider removing /bin/bash in this case
+RUN if bash -c true &> /dev/null; then exit 1; fi
+
+# Make sure the /proc/net/tcp* check fails in this container
+RUN rm /usr/bin/awk
+
+ADD nginx.conf /etc/nginx/conf.d/default.conf

core/src/test/resources/internal-port-check-dockerfile/Dockerfile-tcp

@@ -0,0 +1,9 @@
+FROM nginx:1.17-alpine
+
+# If this fails, you ended up using a base image with bash installed. Consider removing /bin/bash in this case
+RUN if bash -c true &> /dev/null; then exit 1; fi
+
+# Make sure the nc check fails in this container
+RUN rm /usr/bin/nc
+
+ADD nginx.conf /etc/nginx/conf.d/default.conf

core/src/test/resources/internal-port-check-dockerfile/nginx.conf

@@ -0,0 +1,8 @@
+# This configuration makes Nginx listen on port port 8080
+
+server {
+    # Port 8080 is necessary to prove that the command formatting in the /proc/net/tcp* check uses the correct casing for hexadecimal numbers (i.e. 1F90 and not 1f90)
+    listen       8080;
+    # Port 100 is necessary to ensure that the /proc/net/tcp* check also succeeds with trailing zeros in the hexadecimal port
+    listen       100;
+}