Allow to run in strict mode. Fail if any exception is thrown while polling.

spock-core/src/main/java/spock/lang/Retry.java

@@ -99,7 +99,7 @@ enum Mode {
     ITERATION,
 
     /**
-     * Retry the the feature together with the setup and cleanup methods.
+     * Retry the feature together with the setup and cleanup methods.
      */
     SETUP_FEATURE_CLEANUP
   }

spock-core/src/main/java/spock/util/concurrent/PollingConditions.java

@@ -19,6 +19,7 @@
 import org.spockframework.lang.ConditionBlock;
 import org.spockframework.runtime.GroovyRuntimeUtil;
 import org.spockframework.runtime.SpockTimeoutError;
+import org.spockframework.runtime.UnallowedExceptionThrownError;
 import org.spockframework.util.Beta;
 
 /**
@@ -53,6 +54,7 @@ public class PollingConditions {
   private double initialDelay = 0;
   private double delay = 0.1;
   private double factor = 1.0;
+  private boolean strict = false;
 
   /**
    * Returns the timeout (in seconds) until which the conditions have to be satisfied.
@@ -128,11 +130,18 @@ public void setFactor(double factor) {
     this.factor = factor;
   }
 
+  /**
+   * Returns if is strict mode. If strict mode is enabled, will fail if any exception rather than {@link AssertionError} is thrown.
+   * Defaults to {@code false}
+   */
+  public boolean isStrict() {
+    return strict;
+  }
+
   /**
    * Repeatedly evaluates the specified conditions until they are satisfied or the timeout has elapsed.
    *
    * @param conditions the conditions to evaluate
-   *
    * @throws InterruptedException if evaluation is interrupted
    */
   @ConditionBlock
@@ -144,11 +153,10 @@ public void eventually(Closure<?> conditions) throws InterruptedException {
    * Repeatedly evaluates the specified conditions until they are satisfied or the specified timeout (in seconds) has elapsed.
    *
    * @param conditions the conditions to evaluate
-   *
    * @throws InterruptedException if evaluation is interrupted
    */
   @ConditionBlock
-  public void within(double seconds, Closure<?> conditions) throws InterruptedException  {
+  public void within(double seconds, Closure<?> conditions) throws InterruptedException {
     long timeoutMillis = toMillis(seconds);
     long start = System.currentTimeMillis();
     long lastAttempt = 0;
@@ -157,13 +165,16 @@ public void within(double seconds, Closure<?> conditions) throws InterruptedExce
     long currDelay = toMillis(delay);
     int attempts = 0;
 
-    while(true) {
+    while (true) {
       try {
         attempts++;
         lastAttempt = System.currentTimeMillis();
         GroovyRuntimeUtil.invokeClosure(conditions);
         return;
       } catch (Throwable e) {
+        if (strict && !(e instanceof AssertionError)) {
+          throw new UnallowedExceptionThrownError(e.getClass(), e);
+        }
         long elapsedTime = lastAttempt - start;
         if (elapsedTime >= timeoutMillis) {
           String msg = String.format("Condition not satisfied after %1.2f seconds and %d attempts", elapsedTime / 1000d, attempts);

spock-specs/specs.gradle

@@ -9,8 +9,8 @@ configurations {
 }
 
 dependencies {
-  testCompile project(":spock-core")
-  testCompile project(":spock-junit4")
+  testImplementation project(":spock-core")
+  testImplementation project(":spock-junit4")
 
   testRuntime libs.asm
   testRuntime libs.bytebuddy
@@ -27,7 +27,7 @@ targetCompatibility = javaVersion
 // necessary to make @NotYetImplemented transform work (transform that ships
 // with Groovy and statically references third-party class junit.framwork.AssertionFailedError)
 tasks.withType(GroovyCompile) {
-	groovyClasspath += configurations.junit
+  groovyClasspath += configurations.junit
 }
 
 test {

spock-specs/src/test/groovy/spock/util/concurrent/PollingConditionsSpec.groovy

@@ -16,6 +16,7 @@ package spock.util.concurrent
 
 import org.spockframework.runtime.ConditionNotSatisfiedError
 import org.spockframework.runtime.SpockTimeoutError
+import org.spockframework.runtime.UnallowedExceptionThrownError
 import spock.lang.Issue
 import spock.lang.PendingFeature
 import spock.lang.Specification
@@ -154,12 +155,49 @@ class PollingConditionsSpec extends Specification {
     then:
     condition.eventually {
       try {
-        sleep 200;
-        assert secondAttempt;
+        sleep 200
+        assert secondAttempt
       } finally {
         secondAttempt = true
       }
     }
   }
+
+  def "fails if an exception is thrown while polling"() {
+    given:
+    def iteration = 0
+
+    when:
+    new PollingConditions(strict: true).eventually {
+      try {
+        if (iteration < 2) {
+          throw new IllegalStateException("An exception is thrown")
+        }
+        assert true
+      } finally {
+        iteration++
+      }
+    }
+    then:
+    def ex = thrown(UnallowedExceptionThrownError)
+    ex.unallowed == IllegalStateException
+  }
+
+  def "swallow intermediate exceptions while polling"() {
+    given:
+    def iteration = 0
+
+    expect:
+    new PollingConditions(strict: false).eventually {
+      try {
+        if (iteration < 2) {
+          throw new IllegalStateException("An exception is thrown")
+        }
+        assert true
+      } finally {
+        iteration++
+      }
+    }
+  }
 }