diff --git a/src/test/data/validator/logfile.log b/src/test/data/validator/logfile.log
new file mode 100644
index 0000000..4715cc1
--- /dev/null
+++ b/src/test/data/validator/logfile.log
@@ -0,0 +1,7 @@
+Info: validate data...
+Info: assume unknown external objects
+Info: first validation pass...
+Info: second validation pass...
+Info: validate mandatory constraint ModelA.TopicA.ClassA.ConstraintA...
+Error: line 10: ModelA.TopicA.ClassA: tid 1: Mandatory Constraint ModelA.TopicA.ClassA.ConstraintA is not true.
+Info: validate mandatory constraint ModelA.TopicA.ClassA.ConstraintB...
diff --git a/src/test/java/ch/geowerkstatt/interlis/testbed/runner/ValidatorTest.java b/src/test/java/ch/geowerkstatt/interlis/testbed/runner/ValidatorTest.java
new file mode 100644
index 0000000..4643d15
--- /dev/null
+++ b/src/test/java/ch/geowerkstatt/interlis/testbed/runner/ValidatorTest.java
@@ -0,0 +1,48 @@
+package ch.geowerkstatt.interlis.testbed.runner;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public final class ValidatorTest {
+    private static final String CONSTRAINT_A_NAME = "ModelA.TopicA.ClassA.ConstraintA";
+    private static final String CONSTRAINT_B_NAME = "ModelA.TopicA.ClassA.ConstraintB";
+    private static final Path BASE_PATH = Path.of("src/test/data/validator");
+    private static final Path LOG_FILE = BASE_PATH.resolve("logfile.log");
+
+    private TestOptions options;
+
+    @BeforeEach
+    public void setup() {
+        options = new TestOptions(BASE_PATH, Path.of("ilivalidator.jar"));
+    }
+
+    @Test
+    public void containsConstraintError() throws ValidatorException {
+        var validator = new InterlisValidator(options);
+
+        var result = validator.containsConstraintError(LOG_FILE, CONSTRAINT_A_NAME);
+
+        assertTrue(result, "The log file should contain an error for constraint A.");
+    }
+
+    @Test
+    public void noErrorForValidConstraint() throws ValidatorException, IOException {
+        var validator = new InterlisValidator(options);
+
+        var result = validator.containsConstraintError(LOG_FILE, CONSTRAINT_B_NAME);
+
+        assertFalse(result, "The log file should not contain an error for constraint B.");
+
+        try (var lines = Files.lines(LOG_FILE)) {
+            var hasConstraintInfo = lines.anyMatch(line -> line.startsWith("Info:") && line.contains(CONSTRAINT_B_NAME));
+            assertTrue(hasConstraintInfo, "The log file should contain an info message for the constraint.");
+        }
+    }
+}