From 332fe197b2722fc1f97fa50d94012377d1649d55 Mon Sep 17 00:00:00 2001
From: EmadBaroudi <emadaghyadbaroudi@gmail.com>
Date: Thu, 29 Oct 2020 14:16:59 +0100
Subject: [PATCH 1/5] First Green Test

---
 src/test/java/tdd/setup/CalculatorTest.java | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/test/java/tdd/setup/CalculatorTest.java b/src/test/java/tdd/setup/CalculatorTest.java
index 3bf16e9..f85d933 100644
--- a/src/test/java/tdd/setup/CalculatorTest.java
+++ b/src/test/java/tdd/setup/CalculatorTest.java
@@ -16,4 +16,16 @@ void calculatorCanDoTwoPlusTwo() {
         calc.pressEquals();
         assertEquals("4", calc.readScreen());
     }
+    // First Green Test
+    @Test
+    @DisplayName("should Clear the screen and display 0")
+    void calculatorCanClearScreen() {
+        Calculator calc1 = new Calculator();
+        calc1.pressDigitKey(2);
+        calc1.pressOperationKey("+");
+        calc1.pressDigitKey(2);
+        calc1.pressEquals();
+        calc1.pressClearKey();
+        assertEquals("0",calc1.readScreen());
+    }
 }

From fe0712846d360488750db564147ea33db89ad312 Mon Sep 17 00:00:00 2001
From: EmadBaroudi <emadaghyadbaroudi@gmail.com>
Date: Thu, 29 Oct 2020 14:20:27 +0100
Subject: [PATCH 2/5] First Red Test

---
 src/test/java/tdd/setup/CalculatorTest.java | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/test/java/tdd/setup/CalculatorTest.java b/src/test/java/tdd/setup/CalculatorTest.java
index f85d933..6202e20 100644
--- a/src/test/java/tdd/setup/CalculatorTest.java
+++ b/src/test/java/tdd/setup/CalculatorTest.java
@@ -28,4 +28,16 @@ void calculatorCanClearScreen() {
         calc1.pressClearKey();
         assertEquals("0",calc1.readScreen());
     }
+    // First Red Test
+    @Test
+    @DisplayName("should display decimal number")
+    void CalculatorCanDisplayDecimal() {
+        Calculator calc2 = new Calculator();
+        calc2.pressDigitKey(1);
+        calc2.pressDotKey();
+        calc2.pressDigitKey(9);
+        calc2.pressDigitKey(9);
+        calc2.pressEquals();
+        assertEquals("1.99", calc2.readScreen());
+    }
 }

From 6540096128e6403f59153cf92be7943ba143f9ca Mon Sep 17 00:00:00 2001
From: EmadBaroudi <emadaghyadbaroudi@gmail.com>
Date: Thu, 29 Oct 2020 15:09:20 +0100
Subject: [PATCH 3/5] First Red Test bugfix

---
 src/main/java/tdd/setup/Calculator.java     | 2 +-
 src/test/java/tdd/setup/CalculatorTest.java | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/tdd/setup/Calculator.java b/src/main/java/tdd/setup/Calculator.java
index 171f6d6..2d5aa12 100644
--- a/src/main/java/tdd/setup/Calculator.java
+++ b/src/main/java/tdd/setup/Calculator.java
@@ -3,7 +3,7 @@
 // behaviour inspired by https://www.online-calculator.com/
 public class Calculator {
 
-    private String screen = "0";
+    private String screen = "";
 
     private double latestValue;
 
diff --git a/src/test/java/tdd/setup/CalculatorTest.java b/src/test/java/tdd/setup/CalculatorTest.java
index 6202e20..dcd0d89 100644
--- a/src/test/java/tdd/setup/CalculatorTest.java
+++ b/src/test/java/tdd/setup/CalculatorTest.java
@@ -37,7 +37,7 @@ void CalculatorCanDisplayDecimal() {
         calc2.pressDotKey();
         calc2.pressDigitKey(9);
         calc2.pressDigitKey(9);
-        calc2.pressEquals();
+
         assertEquals("1.99", calc2.readScreen());
     }
 }

From b9b9f23b85f7890b6fd62bc49a9a444049872005 Mon Sep 17 00:00:00 2001
From: EmadBaroudi <emadaghyadbaroudi@gmail.com>
Date: Thu, 29 Oct 2020 15:48:12 +0100
Subject: [PATCH 4/5] Second Red Test

---
 src/test/java/tdd/setup/CalculatorTest.java | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/test/java/tdd/setup/CalculatorTest.java b/src/test/java/tdd/setup/CalculatorTest.java
index dcd0d89..f302c6d 100644
--- a/src/test/java/tdd/setup/CalculatorTest.java
+++ b/src/test/java/tdd/setup/CalculatorTest.java
@@ -40,4 +40,15 @@ void CalculatorCanDisplayDecimal() {
 
         assertEquals("1.99", calc2.readScreen());
     }
+    // second Red Test
+    @Test
+    @DisplayName("Should calculate the square root")
+    void CalculatorCanDoSquareroot() {
+        Calculator calc3 = new Calculator();
+        calc3.pressDigitKey(5);
+        calc3.pressOperationKey("sqrt");
+        calc3.pressEquals();
+
+        assertEquals("2.23606797749979", calc3.readScreen());
+    }
 }

From 4ace328309c9d8db7964a278cc8c47d816a037b1 Mon Sep 17 00:00:00 2001
From: EmadBaroudi <emadaghyadbaroudi@gmail.com>
Date: Thu, 29 Oct 2020 15:49:03 +0100
Subject: [PATCH 5/5] Second Red Test bugfix

---
 src/main/java/tdd/setup/Calculator.java | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/main/java/tdd/setup/Calculator.java b/src/main/java/tdd/setup/Calculator.java
index 2d5aa12..c9bf54d 100644
--- a/src/main/java/tdd/setup/Calculator.java
+++ b/src/main/java/tdd/setup/Calculator.java
@@ -47,6 +47,7 @@ public void pressEquals() {
             case "-" -> latestValue - Double.parseDouble(screen);
             case "x" -> latestValue * Double.parseDouble(screen);
             case "/" -> latestValue / Double.parseDouble(screen);
+            case "sqrt" -> Math.sqrt(Double.parseDouble(screen));
             default -> throw new IllegalArgumentException();
         };
         screen = Double.toString(result);