Implement DirectoryHasNChildren Hamcrest Matcher

persistence/src/test/java/bisq/persistence/DirectoryHasNChildren.java

@@ -0,0 +1,54 @@
+/*
+ * This file is part of Bisq.
+ *
+ * Bisq is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Bisq is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Bisq. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package bisq.persistence;
+
+import java.nio.file.Path;
+
+import java.io.File;
+
+import java.util.Objects;
+
+
+
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.hamcrest.TypeSafeMatcher;
+
+public class DirectoryHasNChildren extends TypeSafeMatcher<Path> {
+
+    private final int numberOfChildren;
+
+    public DirectoryHasNChildren(int numberOfChildren) {
+        this.numberOfChildren = numberOfChildren;
+    }
+
+    @Override
+    protected boolean matchesSafely(Path item) {
+        File[] files = item.toFile().listFiles();
+        return Objects.requireNonNull(files).length == numberOfChildren;
+    }
+
+    @Override
+    public void describeTo(Description description) {
+        description.appendText("has " + numberOfChildren + " children");
+    }
+
+    public static Matcher<Path> hasNChildren(int numberOfChildren) {
+        return new DirectoryHasNChildren(numberOfChildren);
+    }
+}