Improve documentation of end-to-end testing

Resolves #1338

Author: fmbenhassine

spring-shell-docs/modules/ROOT/pages/testing.adoc

@@ -141,4 +141,63 @@ public class ShellApplicationEndToEndTests {
 }
 ----
 
-This example demonstrates how to run a Spring Shell application in a test context and verify the output of a command using Spring Boot's `OutputCaptureExtension`.
+This example demonstrates how to run a Spring Shell application in a test context and verify the output of a command using Spring Boot's `OutputCaptureExtension`.
+
+The caveat with this approach is that it is not convenient for testing multiple commands in the same test class due to the fact that the command is passed through the `args` property of the `@SpringBootTest` annotation. For testing multiple commands, it is recommended to use the Spring Shell testing utilities as described in the previous sections. Here is an example of how to test multiple commands using the Spring Shell testing utilities:
+
+[source,java]
+----
+@SpringBootApplication
+public class GreetingShellApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(GreetingShellApplication.class, args);
+	}
+
+	@Command
+	public void hi(CommandContext context) {
+		context.outputWriter().println("Hello world!");
+	}
+
+	@Command
+	public void bye(CommandContext context) {
+		context.outputWriter().println("Goodbye world!");
+	}
+
+}
+
+@ShellTest
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.NONE,
+		useMainMethod = SpringBootTest.UseMainMethod.ALWAYS, classes = { GreetingShellApplication.class },
+		properties = { "spring.shell.interactive.enabled=false" })
+public class ShellApplicationEndToEndMultipleCommandsTests {
+
+	@Test
+	void testCommandExecution(@Autowired ShellTestClient client) throws Exception {
+		// when
+		ShellScreen shellScreen = client.sendCommand("help");
+
+		// then
+		ShellAssertions.assertThat(shellScreen).containsText("AVAILABLE COMMANDS");
+	}
+
+	@Test
+	void testHiCommandExecution(@Autowired ShellTestClient client) throws Exception {
+		// when
+		ShellScreen shellScreen = client.sendCommand("hi");
+
+		// then
+		ShellAssertions.assertThat(shellScreen).containsText("Hello world!");
+	}
+
+	@Test
+	void testByeCommandExecution(@Autowired ShellTestClient client) throws Exception {
+		// when
+		ShellScreen shellScreen = client.sendCommand("bye");
+
+		// then
+		ShellAssertions.assertThat(shellScreen).containsText("Goodbye world!");
+	}
+
+}
+----

spring-shell-test-autoconfigure/src/test/java/org/springframework/shell/test/e2e/GreetingShellApplication.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2025-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.shell.test.e2e;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.shell.core.command.CommandContext;
+import org.springframework.shell.core.command.annotation.Command;
+
+@SpringBootApplication
+public class GreetingShellApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(GreetingShellApplication.class, args);
+	}
+
+	@Command
+	public void hi(CommandContext context) {
+		context.outputWriter().println("Hello world!");
+	}
+
+	@Command
+	public void bye(CommandContext context) {
+		context.outputWriter().println("Goodbye world!");
+	}
+
+}

spring-shell-test-autoconfigure/src/test/java/org/springframework/shell/test/e2e/ShellApplicationEndToEndMultipleCommandsTests.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2026-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.shell.test.e2e;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.shell.test.ShellAssertions;
+import org.springframework.shell.test.ShellScreen;
+import org.springframework.shell.test.ShellTestClient;
+import org.springframework.shell.test.autoconfigure.ShellTest;
+
+@ShellTest
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.NONE,
+		useMainMethod = SpringBootTest.UseMainMethod.ALWAYS, classes = { GreetingShellApplication.class },
+		properties = { "spring.shell.interactive.enabled=false" })
+public class ShellApplicationEndToEndMultipleCommandsTests {
+
+	@Test
+	void testCommandExecution(@Autowired ShellTestClient client) throws Exception {
+		// when
+		ShellScreen shellScreen = client.sendCommand("help");
+
+		// then
+		ShellAssertions.assertThat(shellScreen).containsText("AVAILABLE COMMANDS");
+	}
+
+	@Test
+	void testHiCommandExecution(@Autowired ShellTestClient client) throws Exception {
+		// when
+		ShellScreen shellScreen = client.sendCommand("hi");
+
+		// then
+		ShellAssertions.assertThat(shellScreen).containsText("Hello world!");
+	}
+
+	@Test
+	void testByeCommandExecution(@Autowired ShellTestClient client) throws Exception {
+		// when
+		ShellScreen shellScreen = client.sendCommand("bye");
+
+		// then
+		ShellAssertions.assertThat(shellScreen).containsText("Goodbye world!");
+	}
+
+}