From 01f78a12a29e40b4488679e7ba890025ee75459d Mon Sep 17 00:00:00 2001
From: root <root@Yannick-Laptop.localdomain>
Date: Thu, 29 Oct 2020 11:36:12 +0100
Subject: [PATCH 1/5] =?UTF-8?q?Erster,=20gr=C3=BCner=20Test?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 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 3bf16e9..fe88979 100644
--- a/src/test/java/tdd/setup/CalculatorTest.java
+++ b/src/test/java/tdd/setup/CalculatorTest.java
@@ -16,4 +16,15 @@ void calculatorCanDoTwoPlusTwo() {
         calc.pressEquals();
         assertEquals("4", calc.readScreen());
     }
+
+    @Test
+    @DisplayName("should display result after subtracting two positive numbers")
+    void calculatorCanSubtract() {
+        Calculator calc = new Calculator();
+        calc.pressDigitKey(5);
+        calc.pressOperationKey("-");
+        calc.pressDigitKey(6);
+        calc.pressEquals();
+        assertEquals("-1", calc.readScreen());
+    }
 }

From 96c5a386cb716b0b79c0b206b1e164c1d3314de0 Mon Sep 17 00:00:00 2001
From: root <root@Yannick-Laptop.localdomain>
Date: Thu, 29 Oct 2020 11:44:25 +0100
Subject: [PATCH 2/5] Erster roter Test

---
 src/test/java/tdd/setup/CalculatorTest.java | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/test/java/tdd/setup/CalculatorTest.java b/src/test/java/tdd/setup/CalculatorTest.java
index fe88979..b400c02 100644
--- a/src/test/java/tdd/setup/CalculatorTest.java
+++ b/src/test/java/tdd/setup/CalculatorTest.java
@@ -27,4 +27,17 @@ void calculatorCanSubtract() {
         calc.pressEquals();
         assertEquals("-1", calc.readScreen());
     }
+
+    @Test
+    @DisplayName("should display result after multiplying two numbers and add a third number")
+    void calculatorCanMultiply() {
+        Calculator calc = new Calculator();
+        calc.pressDigitKey(3);
+        calc.pressOperationKey("x");
+        calc.pressDigitKey(6);
+        calc.pressOperationKey("+");
+        calc.pressDigitKey(2);
+        calc.pressEquals();
+        assertEquals("20", calc.readScreen());
+    }
 }

From 505340e3aef26e4d4e23ccf6b1251e0a94e981d5 Mon Sep 17 00:00:00 2001
From: root <root@Yannick-Laptop.localdomain>
Date: Thu, 29 Oct 2020 11:46:33 +0100
Subject: [PATCH 3/5] Bugfix erster roter Test

---
 src/main/java/tdd/setup/Calculator.java | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/main/java/tdd/setup/Calculator.java b/src/main/java/tdd/setup/Calculator.java
index 171f6d6..d6f2a9f 100644
--- a/src/main/java/tdd/setup/Calculator.java
+++ b/src/main/java/tdd/setup/Calculator.java
@@ -30,7 +30,13 @@ public void pressClearKey() {
     }
 
     public void pressOperationKey(String operation)  {
-        latestOperation = operation;
+        if (latestOperation == "") {
+            latestOperation = operation;
+        }
+        else {
+            pressEquals();
+            latestOperation = operation;
+        }
     }
 
     public void pressDotKey() {

From 1431089d4d9a5c3838bbeaadae26dc5b62eb6191 Mon Sep 17 00:00:00 2001
From: root <root@Yannick-Laptop.localdomain>
Date: Thu, 29 Oct 2020 11:47:27 +0100
Subject: [PATCH 4/5] Zweiter roter Test

---
 src/test/java/tdd/setup/CalculatorTest.java | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/test/java/tdd/setup/CalculatorTest.java b/src/test/java/tdd/setup/CalculatorTest.java
index b400c02..28bdca2 100644
--- a/src/test/java/tdd/setup/CalculatorTest.java
+++ b/src/test/java/tdd/setup/CalculatorTest.java
@@ -40,4 +40,14 @@ void calculatorCanMultiply() {
         calc.pressEquals();
         assertEquals("20", calc.readScreen());
     }
+
+    @Test
+    @DisplayName("should display number with dot")
+    void calculatorCanUseDot() {
+        Calculator calc = new Calculator();
+        calc.pressDigitKey(2);
+        calc.pressDotKey();
+        calc.pressDigitKey(5);
+        assertEquals("2.5", calc.readScreen());
+    }
 }

From 13479dac62764959c05e2e955bcb4618d7245b31 Mon Sep 17 00:00:00 2001
From: root <root@Yannick-Laptop.localdomain>
Date: Thu, 29 Oct 2020 11:48:55 +0100
Subject: [PATCH 5/5] Bugfix zweiter roter Test

---
 src/main/java/tdd/setup/Calculator.java | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/main/java/tdd/setup/Calculator.java b/src/main/java/tdd/setup/Calculator.java
index d6f2a9f..f1e3a3e 100644
--- a/src/main/java/tdd/setup/Calculator.java
+++ b/src/main/java/tdd/setup/Calculator.java
@@ -12,11 +12,17 @@ public class Calculator {
     public String readScreen() {
         return screen;
     }
+
     public void pressDigitKey(int digit) {
         if(digit > 9 || digit < 0) throw new IllegalArgumentException();
 
         if(latestOperation.isEmpty()) {
-            screen = screen + digit;
+            if (screen == "0") {
+                screen = Integer.toString(digit);
+            }
+            else {
+                screen = screen + digit;
+            }
         } else {
             latestValue = Double.parseDouble(screen);
             screen = Integer.toString(digit);