add some Formula tests

app/src/androidTest/java/calculator/simplemobiletools/com/simple_calculator/MainActivityTest.java

@@ -50,8 +50,10 @@ public class MainActivityTest {
         press(R.id.btn_6);
         press(R.id.btn_equals);
         checkResult("3.5");
+        checkFormula("-2.5+6");
         press(R.id.btn_equals);
         checkResult("9.5");
+        checkFormula("3.5+6");
     }
 
     @Test
@@ -63,6 +65,7 @@ public class MainActivityTest {
         press(R.id.btn_3);
         press(R.id.btn_equals);
         checkResult("4.8");
+        checkFormula("7.8-3");
     }
 
     @Test
@@ -72,6 +75,7 @@ public class MainActivityTest {
         press(R.id.btn_4);
         press(R.id.btn_equals);
         checkResult("8");
+        checkFormula("2*4");
     }
 
     @Test
@@ -82,6 +86,7 @@ public class MainActivityTest {
         press(R.id.btn_4);
         press(R.id.btn_equals);
         checkResult("2.5");
+        checkFormula("10/4");
     }
 
     @Test
@@ -91,6 +96,7 @@ public class MainActivityTest {
         press(R.id.btn_0);
         press(R.id.btn_equals);
         checkResult("0");
+        checkFormula("8/0");
     }
 
     @Test
@@ -100,6 +106,7 @@ public class MainActivityTest {
         press(R.id.btn_2);
         press(R.id.btn_equals);
         checkResult("1");
+        checkFormula("7%2");
     }
 
     @Test
@@ -109,6 +116,7 @@ public class MainActivityTest {
         press(R.id.btn_3);
         press(R.id.btn_equals);
         checkResult("8");
+        checkFormula("2^3");
     }
 
     @Test
@@ -116,6 +124,7 @@ public class MainActivityTest {
         press(R.id.btn_9);
         press(R.id.btn_root);
         checkResult("3");
+        checkFormula("√9");
     }
 
     @Test
@@ -145,6 +154,7 @@ public class MainActivityTest {
         press(R.id.btn_2);
         press(R.id.btn_equals);
         checkResult("2");
+        checkFormula("");
     }
 
     @Test
@@ -154,29 +164,36 @@ public class MainActivityTest {
         press(R.id.btn_5);
         press(R.id.btn_minus);
         checkResult("7");
+        checkFormula("2+5");
 
         press(R.id.btn_3);
         press(R.id.btn_multiply);
         checkResult("4");
+        checkFormula("7-3");
 
         press(R.id.btn_5);
         press(R.id.btn_divide);
         checkResult("20");
+        checkFormula("4*5");
 
         press(R.id.btn_2);
         press(R.id.btn_modulo);
         checkResult("10");
+        checkFormula("20/2");
 
         press(R.id.btn_4);
         press(R.id.btn_power);
         checkResult("2");
+        checkFormula("10%4");
 
         press(R.id.btn_8);
         press(R.id.btn_modulo);
         checkResult("256");
+        checkFormula("2^8");
 
         press(R.id.btn_root);
         checkResult("16");
+        checkFormula("√256");
 
         press(R.id.btn_clear);
         checkResult("1");
@@ -196,4 +213,8 @@ public class MainActivityTest {
     private void checkResult(String desired) {
         onView(withId(R.id.result)).check(matches(withText(desired)));
     }
+
+    private void checkFormula(String desired) {
+        onView(withId(R.id.formula)).check(matches(withText(desired)));
+    }
 }

app/src/main/java/calculator/simplemobiletools/com/simple_calculator/CalculatorImpl.java

@@ -2,6 +2,7 @@ package calculator.simplemobiletools.com.simple_calculator;
 
 public class CalculatorImpl {
     private String displayedValue;
+    private String displayedFormula;
     private double baseValue;
     private double secondValue;
     private boolean resetValue;
@@ -38,6 +39,7 @@ public class CalculatorImpl {
         lastKey = "";
         lastOperation = "";
         displayedValue = "";
+        displayedFormula = "";
         isFirstOperation = true;
     }
 
@@ -48,6 +50,7 @@ public class CalculatorImpl {
 
     private void setFormula(String value) {
         callback.setFormula(value);
+        displayedFormula = value;
     }
 
     private void updateFormula() {
@@ -90,6 +93,10 @@ public class CalculatorImpl {
         return Double.parseDouble(getDisplayedNumber());
     }
 
+    public String getDisplayedFormula() {
+        return displayedFormula;
+    }
+
     public void handleResult() {
         secondValue = getDisplayedNumberAsDouble();
         calculateResult();
@@ -97,9 +104,8 @@ public class CalculatorImpl {
     }
 
     public void calculateResult() {
-        if (!isFirstOperation) {
+        if (!isFirstOperation)
             updateFormula();
-        }
 
         switch (lastOperation) {
             case Constants.PLUS:

app/src/test/java/calculator/simplemobiletools/com/simple_calculator/MainActivityTest.java

@@ -38,42 +38,49 @@ public class MainActivityTest {
     public void additionTest() {
         String res = calcResult(-1.2, Constants.PLUS, 3.4);
         assertEquals("2.2", res);
+        checkFormula("-1.2+3.4");
     }
 
     @Test
     public void subtractionTest() {
         String res = calcResult(7.8, Constants.MINUS, 2.5);
         assertEquals("5.3", res);
+        checkFormula("7.8-2.5");
     }
 
     @Test
     public void multiplyTest() {
         String res = calcResult(-3.2, Constants.MULTIPLY, 6.6);
         assertEquals("-21.12", res);
+        checkFormula("-3.2*6.6");
     }
 
     @Test
     public void divisionTest() {
         String res = calcResult(18.25, Constants.DIVIDE, 5);
         assertEquals("3.65", res);
+        checkFormula("18.25/5");
     }
 
     @Test
     public void divisionByZero_returnsZero() {
         String res = calcResult(6, Constants.DIVIDE, 0);
         assertEquals("0", res);
+        checkFormula("6/0");
     }
 
     @Test
     public void moduloTest() {
         String res = calcResult(6.5, Constants.MODULO, 3);
         assertEquals("0.5", res);
+        checkFormula("6.5%3");
     }
 
     @Test
     public void powerTest() {
         String res = calcResult(3, Constants.POWER, 6);
         assertEquals("729", res);
+        checkFormula("3^6");
     }
 
     @Test
@@ -81,6 +88,7 @@ public class MainActivityTest {
         setDouble(16);
         handleOperation(Constants.ROOT);
         assertEquals("4", getDisplayedNumber());
+        checkFormula("√16");
     }
 
     @Test
@@ -107,6 +115,7 @@ public class MainActivityTest {
         setDouble(3);
         activity.getCalc().handleResult();
         assertEquals("3", getDisplayedNumber());
+        checkFormula("");
     }
 
     @Test
@@ -116,29 +125,36 @@ public class MainActivityTest {
         setDouble(21);
         handleOperation(Constants.MINUS);
         assertEquals("8.8", getDisplayedNumber());
+        checkFormula("-12.2+21");
 
         setDouble(1.6);
         activity.getCalc().handleEquals();
         assertEquals("7.2", getDisplayedNumber());
+        checkFormula("8.8-1.6");
         activity.getCalc().handleEquals();
         assertEquals("5.6", getDisplayedNumber());
+        checkFormula("7.2-1.6");
 
         handleOperation(Constants.MULTIPLY);
         setDouble(5);
         handleOperation(Constants.DIVIDE);
         assertEquals("28", getDisplayedNumber());
+        checkFormula("5.6*5");
 
         setDouble(4);
         handleOperation(Constants.MODULO);
         assertEquals("7", getDisplayedNumber());
+        checkFormula("28/4");
 
         setDouble(5);
         handleOperation(Constants.POWER);
         assertEquals("2", getDisplayedNumber());
+        checkFormula("7%5");
 
         setDouble(8);
         handleOperation(Constants.ROOT);
         assertEquals("16", getDisplayedNumber());
+        checkFormula("√256");
 
         activity.getCalc().handleClear();
         assertEquals("1", getDisplayedNumber());
@@ -152,6 +168,10 @@ public class MainActivityTest {
         activity.getCalc().handleOperation(operation);
     }
 
+    private void checkFormula(String desired) {
+        assertEquals(desired, getDisplayedFormula());
+    }
+
     private String calcResult(double baseValue, String operation, double secondValue) {
         setDouble(baseValue);
         handleOperation(operation);
@@ -163,4 +183,8 @@ public class MainActivityTest {
     private String getDisplayedNumber() {
         return activity.getCalc().getDisplayedNumber();
     }
+
+    private String getDisplayedFormula() {
+        return activity.getCalc().getDisplayedFormula();
+    }
 }