Provide IT setup

Author: m-dzianishchyts

jjava/pom.xml

@@ -31,6 +31,21 @@
             <groupId>org.apache.maven</groupId>
             <artifactId>maven-model-builder</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>testcontainers</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-simple</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -177,4 +192,4 @@
         </plugins>
     </build>
 
-</project>
+</project>

jjava/src/test/java/org/dflib/jjava/jupyter/kernel/testcontainers/KernelIT.java

@@ -0,0 +1,57 @@
+package org.dflib.jjava.jupyter.kernel.testcontainers;
+
+import org.testcontainers.containers.BindMode;
+import org.testcontainers.containers.Container;
+import org.testcontainers.containers.GenericContainer;
+import org.testcontainers.containers.wait.strategy.Wait;
+
+import java.io.IOException;
+import java.time.Duration;
+
+public abstract class KernelIT {
+
+    private static final String BASE_IMAGE = String.format("eclipse-temurin:%s", Runtime.version().version().get(0));
+    private static final String FS_KERNELSPEC = "../kernelspec/java";
+    private static final String CONTAINER_KERNELSPEC = "/usr/share/jupyter/kernels/java";
+    private static final String WORKING_DIRECTORY = "/test";
+
+    protected static final GenericContainer<?> container;
+
+    static {
+        container = new GenericContainer<>(BASE_IMAGE)
+                .withWorkingDirectory(WORKING_DIRECTORY)
+                .withCommand("bash", "-c", getStartupCommand())
+                .withFileSystemBind(FS_KERNELSPEC, CONTAINER_KERNELSPEC, BindMode.READ_ONLY)
+                .waitingFor(Wait.forSuccessfulCommand(getSuccessfulCommand()))
+                .withStartupTimeout(Duration.ofMinutes(3));
+        container.start();
+    }
+
+    private static String getStartupCommand() {
+        return String.join(" && ",
+                "apt-get update",
+                "apt-get install --no-install-recommends -y python3 python3-pip python3-venv",
+                "python3 -m venv ./venv",
+                venvCommand("pip install jupyter-console --progress-bar off"),
+                "tail -f /dev/null"
+        );
+    }
+
+    private static String getSuccessfulCommand() {
+        return venvCommand("jupyter kernelspec list")
+                + "| grep ' java ' &&"
+                + venvCommand("jupyter console --version");
+    }
+
+    private static String venvCommand(String command) {
+        return WORKING_DIRECTORY + "/venv/bin/" + command;
+    }
+
+    protected Container.ExecResult executeInKernel(String snippet) throws IOException, InterruptedException {
+        return container.execInContainer(
+                "bash",
+                "-c",
+                "echo '" + snippet + "' | " + venvCommand("jupyter console --kernel=java --simple-prompt")
+        );
+    }
+}

jjava/src/test/java/org/dflib/jjava/jupyter/kernel/testcontainers/KernelStartupTestIT.java

@@ -0,0 +1,18 @@
+package org.dflib.jjava.jupyter.kernel.testcontainers;
+
+import org.hamcrest.CoreMatchers;
+import org.hamcrest.MatcherAssert;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.testcontainers.containers.Container;
+
+class KernelStartupTestIT extends KernelIT {
+
+    @Test
+    void startUp() throws Exception {
+        Container.ExecResult snippetResult = executeInKernel("System.out.println(\"Hello world!\");");
+
+        Assertions.assertEquals(0, snippetResult.getExitCode(), snippetResult.getStderr());
+        MatcherAssert.assertThat(snippetResult.getStdout(), CoreMatchers.containsString("Hello world!"));
+    }
+}

pom.xml

@@ -52,6 +52,8 @@
         <junit5.version>5.11.2</junit5.version>
         <hamcrest.version>1.3</hamcrest.version>
         <jimfs.version>1.3.0</jimfs.version>
+        <testcontainers.version>1.20.2</testcontainers.version>
+        <slf4j.version>1.7.36</slf4j.version>
     </properties>
 
     <url>https://github.com/dflib/jjava</url>
@@ -119,6 +121,16 @@
                 <artifactId>jimfs</artifactId>
                 <version>${jimfs.version}</version>
             </dependency>
+            <dependency>
+                <groupId>org.testcontainers</groupId>
+                <artifactId>testcontainers</artifactId>
+                <version>${testcontainers.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.slf4j</groupId>
+                <artifactId>slf4j-simple</artifactId>
+                <version>${slf4j.version}</version>
+            </dependency>
         </dependencies>
     </dependencyManagement>