diff --git a/src/test/java/org/aksw/iguana/cc/query/source/impl/FileLineQuerySourceTest.java b/src/test/java/org/aksw/iguana/cc/query/source/impl/FileLineQuerySourceTest.java
index 7e3ce487..521ec2df 100644
--- a/src/test/java/org/aksw/iguana/cc/query/source/impl/FileLineQuerySourceTest.java
+++ b/src/test/java/org/aksw/iguana/cc/query/source/impl/FileLineQuerySourceTest.java
@@ -78,7 +78,7 @@ public static void deleteTempDirectory() throws IOException {
 
     @Test
     public void testInitialization() throws IOException {
-        assertThrows(NullPointerException.class, () -> new FileLineQuerySource(null));
+        assertThrows(IllegalArgumentException.class, () -> new FileLineQuerySource(null));
         assertDoesNotThrow(() -> new FileLineQuerySource(Files.createTempFile(directory, "Query", ".txt")));
         final var notEmptyFile = Files.createTempFile(directory, "Query", ".txt");
         Files.writeString(notEmptyFile, "not empty");
diff --git a/src/test/java/org/aksw/iguana/cc/query/source/impl/FileSeparatorQuerySourceTest.java b/src/test/java/org/aksw/iguana/cc/query/source/impl/FileSeparatorQuerySourceTest.java
index 0b90506d..dca07659 100644
--- a/src/test/java/org/aksw/iguana/cc/query/source/impl/FileSeparatorQuerySourceTest.java
+++ b/src/test/java/org/aksw/iguana/cc/query/source/impl/FileSeparatorQuerySourceTest.java
@@ -92,7 +92,7 @@ public static void deleteTempDirectory() throws IOException {
 
     @Test
     public void testInitialization() throws IOException {
-        assertThrows(NullPointerException.class, () -> new FileSeparatorQuerySource(null));
+        assertThrows(IllegalArgumentException.class, () -> new FileSeparatorQuerySource(null));
         assertDoesNotThrow(() -> new FileSeparatorQuerySource(Files.createTempFile(directory, "Query", ".txt"), "###"));
         final var notEmptyFile = Files.createTempFile(directory, "Query", ".txt");
         Files.writeString(notEmptyFile, "not empty");