test TreeNumberGenerator

src/main/java/edu/kit/typicalc/view/content/typeinferencecontent/latexcreator/TreeNumberGenerator.java

@@ -14,6 +14,9 @@ public class TreeNumberGenerator {
     }
 
     protected void push() {
+        if (current < 0) {
+            throw new IllegalStateException("The first step must add a step to the tree");
+        }
         numbers.add(current);
     }
 

src/test/java/edu/kit/typicalc/view/content/typeinferencecontent/latexcreator/TreeNumberGeneratorTest.java

@@ -0,0 +1,38 @@
+package edu.kit.typicalc.view.content.typeinferencecontent.latexcreator;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+
+class TreeNumberGeneratorTest {
+
+    @Test
+    void normalFunctionalityTest() {
+        List<Integer> expected = List.of(0, 1, 1, 1, 2, 2, 3);
+        TreeNumberGenerator generator = new TreeNumberGenerator();
+        generator.incrementPush();
+        generator.incrementPush();
+        generator.push();
+        generator.push();
+        generator.incrementPush();
+        generator.push();
+        generator.incrementPush();
+        List<Integer> actual = generator.getNumbers();
+
+        assertEquals(expected.size(), actual.size());
+        for (int i = 0; i < expected.size(); i++) {
+            assertEquals(expected.get(i), actual.get(i));
+        }
+    }
+
+    @Test
+    void pushExceptionTest() {
+        TreeNumberGenerator generator = new TreeNumberGenerator();
+        assertThrows(IllegalStateException.class, generator::push);
+    }
+
+}