diff --git a/numbersTests.c b/numbersTests.c
index 913d4a2..0c39113 100644
--- a/numbersTests.c
+++ b/numbersTests.c
@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include "numbers.h"
 #include "unity.h"
+#include <stdbool.h>
 
 //Initialisierung
 void setUp(void){}
@@ -92,6 +93,73 @@ void test_getDuplicated_finds_correct_duplicate(void)
     free(arr);
 }
 
+// ---------------------------------------------------------------------------
+// Hilfsfunktion: prüft ob createNumbers einen Fehlerzustand signalisiert
+// Du kannst diese später anpassen (z.B. wenn Fehler-Flags eingebaut werden)
+// ---------------------------------------------------------------------------
+static bool did_createNumbers_fail(unsigned int* ptr)
+{
+    return (ptr == NULL);   // aktuell: NULL bedeutet Fehler
+}
+
+
+// ---------------------------------------------------------------------------
+// Test: createNumbers soll bei count < 2 fehlschlagen
+// ---------------------------------------------------------------------------
+void test_createNumbers_rejects_too_small_counts(void)
+{
+    unsigned int* r1 = createNumbers(0);
+    unsigned int* r2 = createNumbers(1);
+
+    TEST_ASSERT_TRUE(did_createNumbers_fail(r1));
+    TEST_ASSERT_TRUE(did_createNumbers_fail(r2));
+}
+
+
+// ---------------------------------------------------------------------------
+// Test: createNumbers(2) soll funktionieren (Minimum gültiger Input)
+// ---------------------------------------------------------------------------
+void test_createNumbers_with_two_elements_is_valid(void)
+{
+    unsigned int* arr = createNumbers(2);
+
+    TEST_ASSERT_FALSE(did_createNumbers_fail(arr));
+    TEST_ASSERT_NOT_NULL(arr);
+
+    // should contain exactly one duplicate
+    unsigned int c0 = countOccurrences(arr, 2, arr[0]);
+    unsigned int c1 = countOccurrences(arr, 2, arr[1]);
+
+    TEST_ASSERT_TRUE((c0 == 2) || (c1 == 2));
+
+    free(arr);
+}
+
+
+// ---------------------------------------------------------------------------
+// Test: getDuplicate() soll Fehler erkennen, wenn arr == NULL
+// ---------------------------------------------------------------------------
+void test_getDuplicate_handles_null_pointer(void)
+{
+    unsigned int result = getDuplicate(NULL, 10);
+// Erwartung: Fehlerzustand → aktuell vermutlich 0 oder UINT_MAX
+    // Wir prüfen nur, DASS es ein Fehler ist:
+    TEST_ASSERT_TRUE(result == 0 || result == UINT_MAX);
+}
+
+
+// ---------------------------------------------------------------------------
+// Test: getDuplicated) soll Fehler erkennen, wenn count < 2
+// ---------------------------------------------------------------------------
+void test_getDuplicate_handles_invalid_count(void)
+{
+    unsigned int dummy[1] = { 5 };
+
+    unsigned int result = getDuplicate(dummy, 1);
+
+    TEST_ASSERT_TRUE(result == 0 || result == UINT_MAX);
+}
+
 // ---------------------------------------------------------------------------
 // main() für Unity
 // ---------------------------------------------------------------------------
@@ -102,6 +170,10 @@ int main(void)
     RUN_TEST(test_createNumbers_returns_valid_array);
     RUN_TEST(test_createNumbers_contains_exactly_one_duplicate);
     RUN_TEST(test_getDuplicated_finds_correct_duplicate);
+    RUN_TEST(test_createNumbers_rejects_too_small_counts);
+    RUN_TEST(test_createNumbers_with_two_elements_is_valid);
+    RUN_TEST(test_getDuplicate_handles_null_pointer);
+    RUN_TEST(test_getDuplicate_handles_invalid_count);
 
     return UNITY_END();
 }
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