Fix @RegisterExtension on CliTester

This reverts commit dfa5480c and rather make the field package private
so that the extension can be registered properly

Closes gh-17266

spring-boot-project/spring-boot-cli/src/test/java/org/springframework/boot/cli/ClassLoaderIntegrationTests.java

@@ -18,6 +18,7 @@ package org.springframework.boot.cli;
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.api.extension.RegisterExtension;
 
 import org.springframework.boot.test.system.CapturedOutput;
 import org.springframework.boot.test.system.OutputCaptureExtension;
@@ -32,7 +33,8 @@ import static org.assertj.core.api.Assertions.assertThat;
 @ExtendWith(OutputCaptureExtension.class)
 class ClassLoaderIntegrationTests {
 
-	private final CliTester cli;
+	@RegisterExtension
+	CliTester cli;
 
 	ClassLoaderIntegrationTests(CapturedOutput capturedOutput) {
 		this.cli = new CliTester("src/test/resources/", capturedOutput);

spring-boot-project/spring-boot-cli/src/test/java/org/springframework/boot/cli/DirectorySourcesIntegrationTests.java

@@ -18,6 +18,7 @@ package org.springframework.boot.cli;
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.api.extension.RegisterExtension;
 
 import org.springframework.boot.test.system.CapturedOutput;
 import org.springframework.boot.test.system.OutputCaptureExtension;
@@ -32,7 +33,8 @@ import static org.assertj.core.api.Assertions.assertThat;
 @ExtendWith(OutputCaptureExtension.class)
 class DirectorySourcesIntegrationTests {
 
-	private final CliTester cli;
+	@RegisterExtension
+	CliTester cli;
 
 	DirectorySourcesIntegrationTests(CapturedOutput capturedOutput) {
 		this.cli = new CliTester("src/test/resources/dir-sample/", capturedOutput);

spring-boot-project/spring-boot-cli/src/test/java/org/springframework/boot/cli/GrabCommandIntegrationTests.java

@@ -22,6 +22,7 @@ import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.api.extension.RegisterExtension;
 
 import org.springframework.boot.cli.command.grab.GrabCommand;
 import org.springframework.boot.test.system.CapturedOutput;
@@ -40,7 +41,8 @@ import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 @ExtendWith(OutputCaptureExtension.class)
 class GrabCommandIntegrationTests {
 
-	private final CliTester cli;
+	@RegisterExtension
+	CliTester cli;
 
 	GrabCommandIntegrationTests(CapturedOutput capturedOutput) {
 		this.cli = new CliTester("src/test/resources/grab-samples/", capturedOutput);

spring-boot-project/spring-boot-cli/src/test/java/org/springframework/boot/cli/ReproIntegrationTests.java

@@ -20,6 +20,7 @@ import java.util.concurrent.ExecutionException;
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.api.extension.RegisterExtension;
 
 import org.springframework.boot.test.system.CapturedOutput;
 import org.springframework.boot.test.system.OutputCaptureExtension;
@@ -37,7 +38,8 @@ import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 @ExtendWith(OutputCaptureExtension.class)
 class ReproIntegrationTests {
 
-	private final CliTester cli;
+	@RegisterExtension
+	CliTester cli;
 
 	ReproIntegrationTests(CapturedOutput capturedOutput) {
 		this.cli = new CliTester("src/test/resources/repro-samples/", capturedOutput);

spring-boot-project/spring-boot-cli/src/test/java/org/springframework/boot/cli/RunCommandIntegrationTests.java

@@ -22,6 +22,7 @@ import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.api.extension.RegisterExtension;
 
 import org.springframework.boot.cli.command.run.RunCommand;
 import org.springframework.boot.test.system.CapturedOutput;
@@ -37,7 +38,8 @@ import static org.assertj.core.api.Assertions.assertThat;
 @ExtendWith(OutputCaptureExtension.class)
 class RunCommandIntegrationTests {
 
-	private final CliTester cli;
+	@RegisterExtension
+	CliTester cli;
 
 	RunCommandIntegrationTests(CapturedOutput capturedOutput) {
 		this.cli = new CliTester("src/it/resources/run-command/", capturedOutput);

spring-boot-project/spring-boot-cli/src/test/java/org/springframework/boot/cli/SampleIntegrationTests.java

@@ -22,6 +22,7 @@ import java.net.URI;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.api.extension.RegisterExtension;
 
 import org.springframework.boot.test.system.CapturedOutput;
 import org.springframework.boot.test.system.OutputCaptureExtension;
@@ -39,7 +40,8 @@ import static org.assertj.core.api.Assertions.assertThat;
 @ExtendWith(OutputCaptureExtension.class)
 class SampleIntegrationTests {
 
-	private final CliTester cli;
+	@RegisterExtension
+	CliTester cli;
 
 	SampleIntegrationTests(CapturedOutput capturedOutput) {
 		this.cli = new CliTester("samples/", capturedOutput);