api: Create a truth subject for io.grpc.Status

Author: jdcormie

api/src/testFixtures/java/io/grpc/testing/StatusSubject.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2026 The gRPC 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
+ *
+ *     http://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 io.grpc.testing;
+
+import static com.google.common.truth.Fact.fact;
+
+import com.google.common.truth.FailureMetadata;
+import com.google.common.truth.Subject;
+import io.grpc.Status;
+import javax.annotation.Nullable;
+
+/** Propositions for {@link Status} subjects. */
+public final class StatusSubject extends Subject {
+
+  private static final Subject.Factory<StatusSubject, Status> statusFactory = new Factory();
+
+  public static Subject.Factory<StatusSubject, Status> status() {
+    return statusFactory;
+  }
+
+  private final Status actual;
+
+  private StatusSubject(FailureMetadata metadata, @Nullable Status subject) {
+    super(metadata, subject);
+    this.actual = subject;
+  }
+
+  /** Fails if the subject is not OK. */
+  public void isOk() {
+    if (actual == null) {
+      failWithActual("expected to be OK but was", "null");
+    } else if (!actual.isOk()) {
+      failWithoutActual(
+          fact("expected to be OK but was", actual.getCode()),
+          fact("description", actual.getDescription()),
+          fact("cause", actual.getCause()));
+    }
+  }
+
+  /** Fails if the subject does not have the given code. */
+  public void hasCode(Status.Code expectedCode) {
+    if (actual == null) {
+      failWithActual("expected to have code " + expectedCode + " but was", "null");
+    } else {
+      check("getCode()").that(actual.getCode()).isEqualTo(expectedCode);
+    }
+  }
+
+  private static final class Factory implements Subject.Factory<StatusSubject, Status> {
+    @Override
+    public StatusSubject createSubject(FailureMetadata metadata, @Nullable Status that) {
+      return new StatusSubject(metadata, that);
+    }
+  }
+}