Introduce IsolatedNetworkTablesExtension

testing/src/main/java/com/team2813/lib2813/testing/junit/jupiter/IsolatedNetworkTablesExtension.java

@@ -0,0 +1,80 @@
+package com.team2813.lib2813.testing.junit.jupiter;
+
+import edu.wpi.first.networktables.NetworkTableInstance;
+import edu.wpi.first.wpilibj.Preferences;
+import org.junit.jupiter.api.extension.AfterEachCallback;
+import org.junit.jupiter.api.extension.Extension;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.jupiter.api.extension.ExtensionContext.Namespace;
+import org.junit.jupiter.api.extension.ExtensionContext.Store;
+import org.junit.jupiter.api.extension.ParameterContext;
+import org.junit.jupiter.api.extension.ParameterResolutionException;
+import org.junit.jupiter.api.extension.ParameterResolver;
+
+/**
+ * JUnit Jupiter extension for providing an isolated NetworkTableInstance to tests.
+ *
+ * <p>Example use:
+ *
+ * <pre>{@code
+ * @ExtendWith(IsolatedNetworkTablesExtension.class)
+ * public final class IntakeTest {
+ *
+ *   @Test
+ *   public void intakeCoral(NetworkTableInstance ntInstance)  {
+ *     // Do something with ntInstance
+ *   }
+ * }
+ * }</pre>
+ */
+public final class IsolatedNetworkTablesExtension
+    implements Extension, AfterEachCallback, ParameterResolver {
+  private static final StoreKey<NetworkTableInstance> NETWORK_TABLE_INSTANCE_KEY =
+      StoreKey.of(NetworkTableInstance.class);
+
+  @Override
+  public void afterEach(ExtensionContext context) {
+    // If this extension created a temporary NetworkTableInstance, close it.
+    var ntInstance = NETWORK_TABLE_INSTANCE_KEY.get(getStore(context));
+    if (ntInstance != null) {
+      // Clear out the listener queue before destroying our temporary NetworkTableInstance.
+      //
+      // This works around a race condition in WPILib where a listener registered by Preferences can
+      // be called after the NetworkTableInstance was closed (see
+      // https://github.com/wpilibsuite/allwpilib/issues/8215).
+      if (!ntInstance.waitForListenerQueue(.1)) {
+        System.err.println(
+            "Timed out waiting for the NetworkTableInstance listener queue to empty (waited 100ms);"
+                + " JVM may crash");
+      }
+
+      Preferences.setNetworkTableInstance(NetworkTableInstance.getDefault());
+      ntInstance.close();
+    }
+  }
+
+  @Override
+  public boolean supportsParameter(
+      ParameterContext parameterContext, ExtensionContext extensionContext)
+      throws ParameterResolutionException {
+    return NetworkTableInstance.class.equals(parameterContext.getParameter().getType());
+  }
+
+  @Override
+  public NetworkTableInstance resolveParameter(
+      ParameterContext parameterContext, ExtensionContext extensionContext)
+      throws ParameterResolutionException {
+    Store store = getStore(extensionContext);
+    NetworkTableInstance ntInstance =
+        NETWORK_TABLE_INSTANCE_KEY.getOrComputeIfAbsent(store, NetworkTableInstance::create);
+
+    ntInstance.startLocal();
+    Preferences.setNetworkTableInstance(ntInstance);
+    return ntInstance;
+  }
+
+  /** Gets the {@link Store} for this extension. */
+  private Store getStore(ExtensionContext context) {
+    return context.getStore(Namespace.create(getClass(), context.getRequiredTestMethod()));
+  }
+}

testing/src/main/java/com/team2813/lib2813/testing/junit/jupiter/StoreKey.java

@@ -0,0 +1,116 @@
+package com.team2813.lib2813.testing.junit.jupiter;
+
+import java.util.function.Supplier;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.jupiter.api.extension.ExtensionContext.Store;
+
+/**
+ * A type-safe key for use in a {@link Store}.
+ *
+ * @param <V> the type for values stored in this store.
+ */
+final class StoreKey<V> {
+  private final Class<V> requiredType;
+
+  /**
+   * Creates a key for storing data of the provided type.
+   *
+   * <p>Values returned from this method should almost always be stored in static final fields.
+   */
+  public static <V> StoreKey<V> of(Class<V> requiredType) {
+    return new StoreKey<>(requiredType);
+  }
+
+  private StoreKey(Class<V> requiredType) {
+    this.requiredType = requiredType;
+  }
+
+  /**
+   * Gets the value that is stored under this key.
+   *
+   * <p>If no value is stored in the current {@link ExtensionContext} for this key, ancestors of the
+   * context will be queried for a value with this key in the {@code Namespace} used to create this
+   * store.
+   *
+   * @param store the store to get data from.
+   * @see #getOrDefault(Store, V)
+   */
+  public V get(Store store) {
+    return store.get(this, requiredType);
+  }
+
+  /**
+   * Gets the value of the specified required type that is stored under this key, or the supplied
+   * {@code defaultValue} if no value is found for this key in this store or in an ancestor.
+   *
+   * <p>If no value is stored in the current {@link ExtensionContext} for this, ancestors of the
+   * context will be queried for a value with this key in the {@code Namespace} used to create this
+   * store.
+   *
+   * @param store the store to get data from.
+   * @param defaultValue the default value.
+   * @return the value; potentially {@code null}.
+   * @see #get(Store)
+   */
+  public V getOrDefault(Store store, V defaultValue) {
+    return store.getOrDefault(this, requiredType, defaultValue);
+  }
+
+  /**
+   * Gets the value of the specified required type that is stored under this key.
+   *
+   * <p>If no value is stored in the current {@link ExtensionContext} for this key, ancestors of the
+   * context will be queried for a value with this key in the {@code Namespace} used to create this
+   * store. If no value is found for this key a new value will be computed by the {@code
+   * valueSupplier}, stored, and returned.
+   *
+   * <p>If {@code requiredType} implements {@link Store.CloseableResource} or {@link AutoCloseable}
+   * (unless the {@code junit.jupiter.extensions.store.close.autocloseable.enabled} configuration
+   * parameter is set to {@code false}), then the {@code close()} method will be invoked on the
+   * stored object when the store is closed.
+   *
+   * @param store the store to use to get and store the data.
+   * @param valueSupplier the function called to create a new value; never {@code null} but may
+   *     return {@code null}.
+   * @return the value; potentially {@code null}.
+   * @see Store.CloseableResource
+   * @see AutoCloseable
+   */
+  public V getOrComputeIfAbsent(Store store, Supplier<V> valueSupplier) {
+    return store.getOrComputeIfAbsent(this, key -> valueSupplier.get(), requiredType);
+  }
+
+  /**
+   * Stores a {@code value} for later retrieval under this key.
+   *
+   * <p>A stored {@code value} is visible in child {@link ExtensionContext ExtensionContexts} for
+   * the store's {@code Namespace} unless they overwrite it.
+   *
+   * <p>If the {@code value} is an instance of {@link Store.CloseableResource} or {@link
+   * AutoCloseable} (unless the {@code junit.jupiter.extensions.store.close.autocloseable.enabled}
+   * configuration parameter is set to {@code false}), then the {@code close()} method will be
+   * invoked on the stored object when the store is closed.
+   *
+   * @param store the store to put data into.
+   * @param value the value to store; may be {@code null}.
+   * @see Store.CloseableResource
+   * @see AutoCloseable
+   */
+  public void put(Store store, V value) {
+    store.put(this, value);
+  }
+
+  /**
+   * Removes the value of the specified required type that was previously stored under this key.
+   *
+   * <p>The value will only be removed in the current {@link ExtensionContext}, not in ancestors. In
+   * addition, the {@link Store.CloseableResource} and {@link AutoCloseable} API will not be honored
+   * for values that are manually removed via this method.
+   *
+   * @param store the store to remove data from.
+   * @return the previous value or {@code null} if no value was present for the specified key.
+   */
+  public V remove(Store store) {
+    return store.remove(this, requiredType);
+  }
+}

testing/src/test/java/com/team2813/lib2813/testing/junit/jupiter/ExtensionAssertions.java

@@ -0,0 +1,37 @@
+package com.team2813.lib2813.testing.junit.jupiter;
+
+import org.junit.platform.testkit.engine.EngineExecutionResults;
+import org.junit.platform.testkit.engine.Events;
+
+/**
+ * A collection of utility methods that support asserting conditions in tests of JUnit Extensions.
+ */
+final class ExtensionAssertions {
+
+  /**
+   * Asserts that the supplied {@code events} do not contain any failures.
+   *
+   * @param events Events fired during execution of a test plan on the JUnit Platform.
+   */
+  public static void assertHasNoFailures(Events events) {
+    events.assertStatistics(
+        stats -> {
+          stats.skipped(0);
+          stats.failed(0);
+        });
+  }
+
+  /**
+   * Asserts that the supplied {@code results} do not contain any failures.
+   *
+   * @param results Results of executing a test plan on the JUnit Platform.
+   */
+  public static void assertHasNoFailures(EngineExecutionResults results) {
+    assertHasNoFailures(results.containerEvents());
+    assertHasNoFailures(results.testEvents());
+  }
+
+  private ExtensionAssertions() {
+    throw new AssertionError("Not instantiable");
+  }
+}

testing/src/test/java/com/team2813/lib2813/testing/junit/jupiter/IsolatedNetworkTablesExtensionTest.java

@@ -0,0 +1,41 @@
+package com.team2813.lib2813.testing.junit.jupiter;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.team2813.lib2813.testing.junit.jupiter.ExtensionAssertions.assertHasNoFailures;
+import static org.junit.platform.engine.discovery.DiscoverySelectors.selectClass;
+
+import edu.wpi.first.networktables.NetworkTableInstance;
+import org.junit.jupiter.api.MethodOrderer;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestMethodOrder;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.platform.testkit.engine.EngineExecutionResults;
+import org.junit.platform.testkit.engine.EngineTestKit;
+
+/** Tests for {@link IsolatedNetworkTablesExtension}. */
+class IsolatedNetworkTablesExtensionTest {
+
+  @ExtendWith(IsolatedNetworkTablesExtension.class)
+  @Tag("ignore-outside-testkit")
+  @TestMethodOrder(MethodOrderer.OrderAnnotation.class)
+  public static class SampleTest {
+
+    @Test
+    public void verifyProvidesNetworkTableParameter(NetworkTableInstance ntInstance) {
+      assertThat(ntInstance).isNotNull();
+      assertThat(ntInstance.getHandle())
+          .isNotEqualTo(NetworkTableInstance.getDefault().getHandle());
+    }
+  } // end SampleTest
+
+  @Test
+  void verifyExtension() {
+    // Act - Run tests in SampleTest
+    EngineExecutionResults results =
+        EngineTestKit.engine("junit-jupiter").selectors(selectClass(SampleTest.class)).execute();
+
+    // Assert - All tests in SampleTest pass
+    assertHasNoFailures(results);
+  }
+}

testing/src/test/java/com/team2813/lib2813/testing/junit/jupiter/WPILibExtensionTest.java

@@ -2,6 +2,7 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
+import static com.team2813.lib2813.testing.junit.jupiter.ExtensionAssertions.assertHasNoFailures;
 import static org.junit.platform.engine.discovery.DiscoverySelectors.selectClass;
 
 import edu.wpi.first.hal.HAL;
@@ -20,7 +21,6 @@
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.platform.testkit.engine.EngineExecutionResults;
 import org.junit.platform.testkit.engine.EngineTestKit;
-import org.junit.platform.testkit.engine.Events;
 
 /** Tests for {@link WPILibExtension}. */
 public class WPILibExtensionTest {
@@ -129,19 +129,6 @@ private void withDriverStationTemporarilyEnabled(Runnable runnable) {
     }
   }
 
-  private void assertHasNoFailures(EngineExecutionResults results) {
-    assertHasNoFailures(results.containerEvents());
-    assertHasNoFailures(results.testEvents());
-  }
-
-  private void assertHasNoFailures(Events events) {
-    events.assertStatistics(
-        stats -> {
-          stats.skipped(0);
-          stats.failed(0);
-        });
-  }
-
   private static class VerifiableCommand extends Command {
     private static final int EXPECTED_EXECUTION_COUNT = 4;
     private int initializedCount = 0;