Update e2e tests

- Add new e2e group to samples which can be used
  with particular tests.
- Relates #401

spring-shell-samples/src/main/java/org/springframework/shell/samples/standard/E2ECommands.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2022 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.samples.standard;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.shell.command.CommandRegistration;
+import org.springframework.shell.standard.ShellComponent;
+import org.springframework.shell.standard.ShellMethod;
+import org.springframework.shell.standard.ShellOption;
+
+/**
+ * Commands used for e2e test.
+ *
+ * @author Janne Valkealahti
+ */
+@ShellComponent
+public class E2ECommands {
+
+	@ShellMethod(key = "e2e anno optional-value")
+	public String testOptionalValue(
+		@ShellOption(defaultValue = ShellOption.NULL) String arg1
+	) {
+		return "Hello " + arg1;
+	}
+
+	@Bean
+	public CommandRegistration testOptionalValueRegistration() {
+		return CommandRegistration.builder()
+			.command("e2e", "reg", "optional-value")
+			.group("E2E Commands")
+			.withOption()
+				.longNames("arg1")
+				.and()
+			.withTarget()
+				.function(ctx -> {
+					String arg1 = ctx.getOptionValue("arg1");
+					return "Hello " + arg1;
+				})
+				.and()
+			.build();
+	}
+
+	@ShellMethod(key = "e2e anno default-value")
+	public String testDefaultValue(
+		@ShellOption(defaultValue = "hi") String arg1
+	) {
+		return "Hello " + arg1;
+	}
+
+	@Bean
+	public CommandRegistration testDefaultValueRegistration() {
+		return CommandRegistration.builder()
+			.command("e2e", "reg", "default-value")
+			.group("E2E Commands")
+			.withOption()
+				.longNames("arg1")
+				.defaultValue("hi")
+				.and()
+			.withTarget()
+				.function(ctx -> {
+					String arg1 = ctx.getOptionValue("arg1");
+					return "Hello " + arg1;
+				})
+				.and()
+			.build();
+	}
+}