diff --git a/src/test/java/de/tla2b/prettyprintb/ActionsTest.java b/src/test/java/de/tla2b/prettyprintb/ActionsTest.java
index adaad8aa28ca5df650ab507be55212385ba07d3c..1bdb1c7968ef2637c108894cda4d82b3715b5413 100644
--- a/src/test/java/de/tla2b/prettyprintb/ActionsTest.java
+++ b/src/test/java/de/tla2b/prettyprintb/ActionsTest.java
@@ -1,5 +1,6 @@
 package de.tla2b.prettyprintb;
 
+import de.tla2b.exceptions.SemanticErrorException;
 import org.junit.Ignore;
 import org.junit.Test;
 
@@ -63,4 +64,15 @@ public class ActionsTest {
 			+ "END";
 		compare(expected, module);
 	}
+
+	@Test(expected = SemanticErrorException.class)
+	public void testMissingInit() throws Exception {
+		final String module = "-------------- MODULE Testing ----------------\n"
+				+ "EXTENDS Naturals \n"
+				+ "VARIABLES x \n"
+				+ "Next == x'=x+1 \n"
+				+ "=================================";
+
+		compare("MACHINE Testing END", module);
+	}
 }
diff --git a/src/test/java/de/tla2b/prettyprintb/LogicOperatorsTest.java b/src/test/java/de/tla2b/prettyprintb/LogicOperatorsTest.java
index 8899544f22bb9e2eb152e0a286eed8abe7042466..2291c75a9014d6b001580ac4b9ac3027f3c35599 100644
--- a/src/test/java/de/tla2b/prettyprintb/LogicOperatorsTest.java
+++ b/src/test/java/de/tla2b/prettyprintb/LogicOperatorsTest.java
@@ -80,6 +80,19 @@ public class LogicOperatorsTest {
 		compare(expected, module);
 	}
 
+	@Test
+	public void testNegation2() throws Exception {
+		final String module = "-------------- MODULE Testing ----------------\n"
+				+ "CONSTANTS a,b \n"
+				+ "ASSUME a \\in BOOLEAN /\\ b = ~a \n"
+				+ "=================================";
+
+		final String expected = "MACHINE Testing\n"
+				+ "CONSTANTS a, b \n"
+				+ "PROPERTIES a : BOOL & b : BOOL & (a : BOOL & b = bool(not(a = TRUE))) \n" + "END";
+		compare(expected, module);
+	}
+
 	/*
 	 * Implication and Equivalence: =>, \equiv
 	 */