Preserve eliminating nulls from instances

A little bit unfortunate and assuming, but it is existing behavior and
must be preserved to avoid breaking stuff.

pom.xml

@@ -93,6 +93,11 @@
             <artifactId>mockito-core</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>commons-io</groupId>
             <artifactId>commons-io</artifactId>

src/main/java/no/digipost/DiggBase.java

@@ -21,6 +21,7 @@
 
 import java.util.ArrayDeque;
 import java.util.Deque;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Spliterator;
 import java.util.function.Consumer;
@@ -247,7 +248,9 @@ public static <T> Stream<Exception> forceOnAll(ThrowingConsumer<? super T, ? ext
      * @return the Stream with exceptions, if any
      */
     public static <T> Stream<Exception> forceOnAll(ThrowingConsumer<? super T, ? extends Exception> action, Stream<T> instances) {
-        return StreamSupport.stream(new FlatMapToExceptionSpliterator<>(action, instances.spliterator()), instances.isParallel());
+        return StreamSupport.stream(
+                new FlatMapToExceptionSpliterator<>(action, instances.filter(Objects::nonNull).spliterator()),
+                instances.isParallel());
     }
 
     private static final class FlatMapToExceptionSpliterator<W> implements Spliterator<Exception> {

src/test/java/no/digipost/DiggBaseTest.java

@@ -20,7 +20,10 @@
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.Timeout;
+import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
 import org.quicktheories.WithQuickTheories;
 import org.quicktheories.core.Gen;
 import org.quicktheories.dsl.TheoryBuilder;
@@ -45,6 +48,7 @@
 import static no.digipost.DiggBase.friendlyName;
 import static no.digipost.DiggBase.nonNull;
 import static no.digipost.DiggBase.throwingAutoClose;
+import static no.digipost.DiggCollectors.toSingleExceptionWithSuppressed;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.containsString;
@@ -55,6 +59,7 @@
 import static org.hamcrest.Matchers.isA;
 import static org.hamcrest.Matchers.sameInstance;
 import static org.junit.jupiter.api.Assertions.assertAll;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.fail;
 import static org.mockito.Mockito.doNothing;
@@ -66,6 +71,7 @@
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static uk.co.probablyfine.matchers.Java8Matchers.where;
 
+@ExtendWith(MockitoExtension.class)
 public class DiggBaseTest implements WithQuickTheories {
 
     @Test
@@ -277,6 +283,16 @@ void worksWithParalellStreams() {
                     failures * 3, is(successes.get()));
         }
 
+        @Test
+        void doesNotInvokeOperationOnNulls(@Mock AutoCloseable resource) throws Exception {
+            Optional<RuntimeException> exception = forceOnAll(AutoCloseable::close, resource, null, resource, null, resource)
+                    .collect(toSingleExceptionWithSuppressed())
+                    .map(DiggExceptions::asUnchecked);
+            assertAll(
+                    () -> verify(resource, times(3)).close(),
+                    () -> assertDoesNotThrow(() -> exception.ifPresent(e -> { throw e; })));
+        }
+
     }
 
 }