diff --git a/poincare/test/helper.cpp b/poincare/test/helper.cpp
index 80d5706bb..ecd631b65 100644
--- a/poincare/test/helper.cpp
+++ b/poincare/test/helper.cpp
@@ -40,7 +40,7 @@ void quiz_assert_log_if_failure(bool test, TreeHandle tree) {
 void assert_parsed_expression_process_to(const char * expression, const char * result, ExpressionNode::ReductionTarget target, Preferences::ComplexFormat complexFormat, Preferences::AngleUnit angleUnit, ExpressionNode::SymbolicComputation symbolicComputation, ProcessExpression process, int numberOfSignifiantDigits) {
   Shared::GlobalContext globalContext;
   Expression e = parse_expression(expression, &globalContext, false);
-  Expression m = process(e, &globalContext, target, complexFormat, angleUnit, symbolicComputation);
+  Expression m = process(e, ExpressionNode::ReductionContext(&globalContext, complexFormat, angleUnit, target, symbolicComputation));
   constexpr int bufferSize = 500;
   char buffer[bufferSize];
   m.serialize(buffer, bufferSize, DecimalMode, numberOfSignifiantDigits);
@@ -85,12 +85,12 @@ void assert_simplify(const char * expression, Preferences::AngleUnit angleUnit,
 }
 
 void assert_parsed_expression_simplify_to(const char * expression, const char * simplifiedExpression, ExpressionNode::ReductionTarget target, Preferences::AngleUnit angleUnit, Preferences::ComplexFormat complexFormat, ExpressionNode::SymbolicComputation symbolicComputation) {
-  assert_parsed_expression_process_to(expression, simplifiedExpression, target, complexFormat, angleUnit, symbolicComputation, [](Expression e, Context * context, ExpressionNode::ReductionTarget target, Preferences::ComplexFormat complexFormat, Preferences::AngleUnit angleUnit, ExpressionNode::SymbolicComputation symbolicComputation) {
+  assert_parsed_expression_process_to(expression, simplifiedExpression, target, complexFormat, angleUnit, symbolicComputation, [](Expression e, ExpressionNode::ReductionContext reductionContext) {
       Expression copy = e.clone();
-      if (target == ExpressionNode::ReductionTarget::User) {
-        copy.simplifyAndApproximate(&copy, nullptr, context, complexFormat, angleUnit, symbolicComputation);
+      if (reductionContext.target() == ExpressionNode::ReductionTarget::User) {
+        copy.simplifyAndApproximate(&copy, nullptr, reductionContext.context(), reductionContext.complexFormat(), reductionContext.angleUnit(), reductionContext.symbolicComputation());
       } else {
-        copy = copy.simplify(ExpressionNode::ReductionContext(context, complexFormat, angleUnit, target, symbolicComputation));
+        copy = copy.simplify(reductionContext);
       }
       if (copy.isUninitialized()) {
         return e;
@@ -103,8 +103,8 @@ template<typename T>
 void assert_expression_approximates_to(const char * expression, const char * approximation, Preferences::AngleUnit angleUnit, Preferences::ComplexFormat complexFormat, int numberOfSignificantDigits) {
   int numberOfDigits = sizeof(T) == sizeof(double) ? PrintFloat::k_numberOfStoredSignificantDigits : PrintFloat::k_numberOfPrintedSignificantDigits;
   numberOfDigits = numberOfSignificantDigits > 0 ? numberOfSignificantDigits : numberOfDigits;
-  assert_parsed_expression_process_to(expression, approximation, SystemForApproximation, complexFormat, angleUnit, ReplaceAllSymbolsWithDefinitionsOrUndefined, [](Expression e, Context * context, ExpressionNode::ReductionTarget target, Preferences::ComplexFormat complexFormat, Preferences::AngleUnit angleUnit, ExpressionNode::SymbolicComputation symbolicComputation) {
-      return e.approximate<T>(context, complexFormat, angleUnit);
+  assert_parsed_expression_process_to(expression, approximation, SystemForApproximation, complexFormat, angleUnit, ReplaceAllSymbolsWithDefinitionsOrUndefined, [](Expression e, ExpressionNode::ReductionContext reductionContext) {
+      return e.approximate<T>(reductionContext.context(), reductionContext.complexFormat(), reductionContext.angleUnit());
     }, numberOfDigits);
 }
 
diff --git a/poincare/test/helper.h b/poincare/test/helper.h
index bf7b25a4f..898972f5f 100644
--- a/poincare/test/helper.h
+++ b/poincare/test/helper.h
@@ -24,7 +24,7 @@ constexpr Poincare::Preferences::PrintFloatMode EngineeringMode = Poincare::Pref
 void quiz_assert_print_if_failure(bool test, const char * information);
 void quiz_assert_log_if_failure(bool test, Poincare::TreeHandle tree);
 
-typedef Poincare::Expression (*ProcessExpression)(Poincare::Expression, Poincare::Context * context, Poincare::ExpressionNode::ReductionTarget target, Poincare::Preferences::ComplexFormat complexFormat, Poincare::Preferences::AngleUnit angleUnit, Poincare::ExpressionNode::SymbolicComputation symbolicComputation); //TODO LEA replace with reductionContext
+typedef Poincare::Expression (*ProcessExpression)(Poincare::Expression, Poincare::ExpressionNode::ReductionContext reductionContext);
 
 void assert_parsed_expression_process_to(const char * expression, const char * result, Poincare::ExpressionNode::ReductionTarget target, Poincare::Preferences::ComplexFormat complexFormat, Poincare::Preferences::AngleUnit angleUnit, Poincare::ExpressionNode::SymbolicComputation symbolicComputation, ProcessExpression process, int numberOfSignifiantDigits = Poincare::PrintFloat::k_numberOfStoredSignificantDigits);