diff --git a/src/test/java/ch/unibas/dmi/dbis/cs108/casono/common/tokenizer/StateTest.java b/src/test/java/ch/unibas/dmi/dbis/cs108/casono/common/tokenizer/StateTest.java
new file mode 100644
index 0000000..db0b4fe
--- /dev/null
+++ b/src/test/java/ch/unibas/dmi/dbis/cs108/casono/common/tokenizer/StateTest.java
@@ -0,0 +1,60 @@
+package ch.unibas.dmi.dbis.cs108.casono.common.tokenizer;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class StateTest {
+    @Test
+    void testConstructor() {
+        String input = "hello";
+        State state = new State(input);
+        assertEquals(input, state.input);
+        assertEquals(0, state.pos);
+        assertEquals(1, state.line);
+        assertEquals(1, state.column);
+        assertTrue(state.tokens.isEmpty());
+    }
+
+    @Test
+    void testCurrent() {
+        String input = "abc";
+        State state = new State(input);
+        assertEquals('a', state.current());
+        state.advance();
+        assertEquals('b', state.current());
+    }
+
+    @Test
+    void testPeek() {
+        String input = "abc";
+        State state = new State(input);
+        assertEquals('b', state.peek());
+        state.advance();
+        assertEquals('c', state.peek());
+        state.advance();
+        assertEquals('\0', state.peek()); // End of input
+    }
+
+    @Test
+    void testAdvance() {
+        String input = "abc";
+        State state = new State(input);
+        assertEquals(0, state.pos);
+        assertEquals(1, state.column);
+        state.advance();
+        assertEquals(1, state.pos);
+        assertEquals(2, state.column);
+    }
+
+    @Test
+    void testIsEof() {
+        String input = "a";
+        State state = new State(input);
+        assertFalse(state.isEof());
+        state.advance();
+        assertTrue(state.isEof());
+    }
+}