diff --git a/apps/calculation/Makefile b/apps/calculation/Makefile
index e5f464fcf..22457b7c3 100644
--- a/apps/calculation/Makefile
+++ b/apps/calculation/Makefile
@@ -11,5 +11,10 @@ app_objs += $(addprefix apps/calculation/,\
   text_field.o\
 )
 
+tests += $(addprefix apps/calculation/test/,\
+  calculation_store.cpp\
+)
+test_objs += $(addprefix apps/calculation/, calculation.o calculation_store.o)
+
 app_images += apps/calculation/calculation_icon.png
 
diff --git a/apps/calculation/calculation.cpp b/apps/calculation/calculation.cpp
index 182b769d3..c8c4a2015 100644
--- a/apps/calculation/calculation.cpp
+++ b/apps/calculation/calculation.cpp
@@ -5,6 +5,8 @@ using namespace Poincare;
 namespace Calculation {
 
 Calculation::Calculation() :
+  m_inputText(""),
+  m_outputText(""),
   m_input(nullptr),
   m_inputLayout(nullptr),
   m_output(nullptr),
diff --git a/apps/calculation/calculation_store.h b/apps/calculation/calculation_store.h
index 15eeb0b72..598b7b32a 100644
--- a/apps/calculation/calculation_store.h
+++ b/apps/calculation/calculation_store.h
@@ -5,8 +5,6 @@
 
 namespace Calculation {
 
-// TODO: make tests for the ring buffer
-
 class CalculationStore {
 public:
   CalculationStore();
@@ -16,8 +14,8 @@ public:
   void deleteAll();
   int numberOfCalculations();
   void tidy();
-private:
   static constexpr int k_maxNumberOfCalculations = 10;
+private:
   int m_startIndex;
   Calculation m_calculations[k_maxNumberOfCalculations];
 };
diff --git a/apps/calculation/test/.calculation_store.cpp.swp b/apps/calculation/test/.calculation_store.cpp.swp
new file mode 100644
index 000000000..27f3ccb66
Binary files /dev/null and b/apps/calculation/test/.calculation_store.cpp.swp differ
diff --git a/apps/calculation/test/calculation_store.cpp b/apps/calculation/test/calculation_store.cpp
new file mode 100644
index 000000000..c581ecf08
--- /dev/null
+++ b/apps/calculation/test/calculation_store.cpp
@@ -0,0 +1,45 @@
+#include <quiz.h>
+#include <string.h>
+#include <assert.h>
+#include "../calculation_store.h"
+
+using namespace Poincare;
+using namespace Calculation;
+
+QUIZ_CASE(calculation_store) {
+  GlobalContext globalContext;
+  CalculationStore store;
+  assert(CalculationStore::k_maxNumberOfCalculations == 10);
+  for (int i = 0; i < CalculationStore::k_maxNumberOfCalculations; i++) {
+    char text[2] = {(char)(i+'0'), 0};
+    store.push(text, &globalContext);
+    assert(store.numberOfCalculations() == i+1);
+  }
+  /* Store is now {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} */
+  for (int i = 0; i < CalculationStore::k_maxNumberOfCalculations; i++) {
+    assert(store.calculationAtIndex(i)->input()->approximate(globalContext) == i);
+  }
+  store.push("10", &globalContext);
+  /* Store is now {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} */
+  assert(store.calculationAtIndex(9)->input()->approximate(globalContext) == 10);
+  assert(store.calculationAtIndex(0)->input()->approximate(globalContext) == 1);
+  for (int i = 0; i < CalculationStore::k_maxNumberOfCalculations; i++) {
+    char text[2] = {(char)(i+'0'), 0};
+    store.push(text, &globalContext);
+    assert(store.numberOfCalculations() == 10);
+  }
+  /* Store is now {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} */
+  for (int i = 9; i > 0; i = i-2) {
+   store.deleteCalculationAtIndex(i);
+  }
+  /* Store is now {0, 2, 4, 6, 8} */
+  for (int i = 0; i < 5; i++) {
+    assert(store.calculationAtIndex(i)->input()->approximate(globalContext) == 2.0f*i);
+  }
+  for (int i = 5; i < CalculationStore::k_maxNumberOfCalculations; i++) {
+    char text[3] = {(char)(i+'0'), 0};
+    store.push(text, &globalContext);
+    assert(store.numberOfCalculations() == i+1);
+  }
+  /* Store is now {0, 2, 4, 6, 8, 5, 6, 7, 8, 9} */
+}
diff --git a/quiz/Makefile b/quiz/Makefile
index 2028a6f7c..840e30d9a 100644
--- a/quiz/Makefile
+++ b/quiz/Makefile
@@ -8,7 +8,7 @@ $(symbols_file): $(tests)
 	@awk -f quiz/src/symbols.awk $(tests) > $@
 
 runner_objs += $(addprefix quiz/src/, runner.o symbols.o i18n.o)
-test_objs = $(subst .c,.o, $(subst .cpp,.o,$(tests)))
+test_objs += $(subst .c,.o, $(subst .cpp,.o,$(tests)))
 
 test.$(EXE): $(runner_objs) $(test_objs)