diff --git a/alpha-api/src/main/java/at/ac/tuwien/kr/alpha/api/programs/atoms/ModuleAtom.java b/alpha-api/src/main/java/at/ac/tuwien/kr/alpha/api/programs/atoms/ModuleAtom.java
index 17cabfc4a..42fedae92 100644
--- a/alpha-api/src/main/java/at/ac/tuwien/kr/alpha/api/programs/atoms/ModuleAtom.java
+++ b/alpha-api/src/main/java/at/ac/tuwien/kr/alpha/api/programs/atoms/ModuleAtom.java
@@ -25,13 +25,34 @@ public interface ModuleAtom extends Atom {
 	@Override
 	ModuleAtom substitute(Substitution substitution);
 
+	@Override
+	ModuleAtom withTerms(List<Term> terms);
+
 	interface ModuleInstantiationMode {
 		Optional<Integer> requestedAnswerSets();
 
 		ModuleInstantiationMode ALL = Optional::empty;
 
 		static ModuleInstantiationMode forNumAnswerSets(int answerSets) {
-			return () -> Optional.of(answerSets);
+			return new ModuleInstantiationMode() {
+				@Override
+				public Optional<Integer> requestedAnswerSets() {
+					return Optional.of(answerSets);
+				}
+
+				@Override
+				public int hashCode() {
+					return answerSets;
+				}
+
+				@Override
+				public boolean equals(Object obj) {
+					if (!(obj instanceof ModuleInstantiationMode)) {
+						return false;
+					}
+					return ((ModuleInstantiationMode) obj).requestedAnswerSets().equals(this.requestedAnswerSets());
+				}
+			};
 		}
 
 	}
diff --git a/alpha-commons/src/main/java/at/ac/tuwien/kr/alpha/commons/programs/atoms/ModuleAtomImpl.java b/alpha-commons/src/main/java/at/ac/tuwien/kr/alpha/commons/programs/atoms/ModuleAtomImpl.java
index a971214c4..72178d72b 100644
--- a/alpha-commons/src/main/java/at/ac/tuwien/kr/alpha/commons/programs/atoms/ModuleAtomImpl.java
+++ b/alpha-commons/src/main/java/at/ac/tuwien/kr/alpha/commons/programs/atoms/ModuleAtomImpl.java
@@ -2,7 +2,6 @@
 
 import at.ac.tuwien.kr.alpha.api.grounder.Substitution;
 import at.ac.tuwien.kr.alpha.api.programs.Predicate;
-import at.ac.tuwien.kr.alpha.api.programs.atoms.Atom;
 import at.ac.tuwien.kr.alpha.api.programs.atoms.ModuleAtom;
 import at.ac.tuwien.kr.alpha.api.programs.literals.ModuleLiteral;
 import at.ac.tuwien.kr.alpha.api.programs.terms.Term;
@@ -50,7 +49,7 @@ public ModuleInstantiationMode getInstantiationMode() {
 	}
 
 	@Override
-	public Atom withTerms(List<Term> terms) {
+	public ModuleAtom withTerms(List<Term> terms) {
 		if (terms.size() != this.input.size() + this.output.size()) {
 			throw new IllegalArgumentException(
 					"Cannot apply term list " + terms + " to module atom " + this + ", terms has invalid size!");
diff --git a/alpha-commons/src/test/java/at/ac/tuwien/kr/alpha/commons/programs/atoms/ModuleAtomImplTest.java b/alpha-commons/src/test/java/at/ac/tuwien/kr/alpha/commons/programs/atoms/ModuleAtomImplTest.java
new file mode 100644
index 000000000..efa2d1353
--- /dev/null
+++ b/alpha-commons/src/test/java/at/ac/tuwien/kr/alpha/commons/programs/atoms/ModuleAtomImplTest.java
@@ -0,0 +1,74 @@
+package at.ac.tuwien.kr.alpha.commons.programs.atoms;
+
+import java.util.List;
+
+import at.ac.tuwien.kr.alpha.api.programs.atoms.ModuleAtom;
+import at.ac.tuwien.kr.alpha.commons.programs.terms.Terms;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class ModuleAtomImplTest {
+
+	@Test
+	public void withTerms() {
+		ModuleAtom moduleAtom = new ModuleAtomImpl("someModule",
+				List.of(Terms.newVariable("X"), Terms.newVariable("Y")),
+				List.of(Terms.newVariable("Z")), ModuleAtom.ModuleInstantiationMode.ALL);
+		ModuleAtom newModuleAtom = moduleAtom.withTerms(List.of(Terms.newConstant(1), Terms.newConstant(2), Terms.newConstant(3)));
+		// Check correct construction of original atom (also check that withTerms didn't modify the original atom)
+		assertEquals(moduleAtom.getInput().size(), 2);
+		assertEquals(moduleAtom.getOutput().size(), 1);
+		assertEquals(moduleAtom.getModuleName(), "someModule");
+		assertEquals(moduleAtom.getInstantiationMode(), ModuleAtom.ModuleInstantiationMode.ALL);
+		// Check terms of new atom
+		assertEquals(newModuleAtom.getInput().size(), 2);
+		assertEquals(newModuleAtom.getOutput().size(), 1);
+		assertEquals(newModuleAtom.getModuleName(), "someModule");
+		assertEquals(newModuleAtom.getInstantiationMode(), ModuleAtom.ModuleInstantiationMode.ALL);
+		assertEquals(List.of(Terms.newConstant(1), Terms.newConstant(2)), newModuleAtom.getInput());
+		assertEquals(List.of(Terms.newConstant(3)), newModuleAtom.getOutput());
+	}
+
+	@Test
+	public void withTermsNewTermsTooLong() {
+		ModuleAtom moduleAtom = new ModuleAtomImpl("someModule",
+				List.of(Terms.newVariable("X"), Terms.newVariable("Y")),
+				List.of(Terms.newVariable("Z")), ModuleAtom.ModuleInstantiationMode.ALL);
+		assertThrows(IllegalArgumentException.class,
+				() -> moduleAtom.withTerms(
+						List.of(Terms.newConstant(1), Terms.newConstant(2),
+								Terms.newConstant(3), Terms.newConstant(4))));
+	}
+
+	@Test
+	public void withTermsNewTermsTooShort() {
+		ModuleAtom moduleAtom = new ModuleAtomImpl("someModule",
+				List.of(Terms.newVariable("X"), Terms.newVariable("Y")),
+				List.of(Terms.newVariable("Z")), ModuleAtom.ModuleInstantiationMode.ALL);
+		assertThrows(IllegalArgumentException.class,
+				() -> moduleAtom.withTerms(List.of(Terms.newConstant(1))));
+	}
+
+	@Test
+	public void moduleAtomsEqual() {
+		ModuleAtom m1 = new ModuleAtomImpl("someModule",
+				List.of(Terms.newVariable("X"), Terms.newVariable("Y")),
+				List.of(Terms.newVariable("Z")), ModuleAtom.ModuleInstantiationMode.ALL);
+		ModuleAtom m2 = new ModuleAtomImpl("someModule",
+				List.of(Terms.newVariable("X"), Terms.newVariable("Y")),
+				List.of(Terms.newVariable("Z")), ModuleAtom.ModuleInstantiationMode.ALL);
+		assertEquals(m1, m2);
+		assertEquals(m1.hashCode(), m2.hashCode());
+
+		ModuleAtom m3 = new ModuleAtomImpl("someModule",
+				List.of(Terms.newVariable("X"), Terms.newVariable("Y")),
+				List.of(Terms.newVariable("Z")), ModuleAtom.ModuleInstantiationMode.forNumAnswerSets(3));
+		ModuleAtom m4 = new ModuleAtomImpl("someModule",
+				List.of(Terms.newVariable("X"), Terms.newVariable("Y")),
+				List.of(Terms.newVariable("Z")), ModuleAtom.ModuleInstantiationMode.forNumAnswerSets(3));
+		assertNotEquals(m1, m3);
+		assertEquals(m3, m4);
+	}
+
+}