From f9891c392a926260bae6b6cd18806958642f131d Mon Sep 17 00:00:00 2001
From: Lukas Reichwein <codeisnotevil@gmail.com>
Date: Wed, 26 Jun 2019 17:16:09 +0200
Subject: [PATCH] The funktionality Linked Matricies Check

---
 .../com/ugsbo/matrixcalc/MatrixCalcMath.java  | 10 +++++-
 .../matrixcalc/MatrixMultiplicationTest.java  | 31 +++++++++++++++----
 2 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/src/main/java/com/ugsbo/matrixcalc/MatrixCalcMath.java b/src/main/java/com/ugsbo/matrixcalc/MatrixCalcMath.java
index 4725418..d18d9cd 100644
--- a/src/main/java/com/ugsbo/matrixcalc/MatrixCalcMath.java
+++ b/src/main/java/com/ugsbo/matrixcalc/MatrixCalcMath.java
@@ -27,7 +27,15 @@ public class MatrixCalcMath {
      */
     public boolean checkIfMatriciesAreLinked(Double[][] matrixA, Double[][] matrixB) {
         // TODO Check if the number of Rows of Matrix A equal to the coulums of Matrix B
-        return false;
+        if (matrixA != null) {
+            if (matrixA[0].length == matrixB.length) {
+                return true;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
     }
 
     /**
diff --git a/src/test/java/com/ugsbo/matrixcalc/MatrixMultiplicationTest.java b/src/test/java/com/ugsbo/matrixcalc/MatrixMultiplicationTest.java
index 9fc0dc9..913227d 100644
--- a/src/test/java/com/ugsbo/matrixcalc/MatrixMultiplicationTest.java
+++ b/src/test/java/com/ugsbo/matrixcalc/MatrixMultiplicationTest.java
@@ -1,5 +1,6 @@
 package com.ugsbo.matrixcalc;
 
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import org.junit.Test;
@@ -8,12 +9,30 @@ import org.junit.Test;
  * Testet die Matrix Multiplication funkionalität
  */
 public class MatrixMultiplicationTest {
-    /**
-     * This Test only tests that the assertTrue funktion works like expected.
-     */
+
+    @Test
+    public void MatrixAIsLinkedToMatrixBSouldBeTrue() {
+        MatrixCalcMath math = new MatrixCalcMath();
+        Double[][] matrixA = new Double[1][2];
+        Double[][] matrixB = new Double[2][1];
+        assertTrue("Matrix A is Linked to B but it is not detected that way",
+                math.checkIfMatriciesAreLinked(matrixA, matrixB));
+    }
+
+    @Test
+    public void MatrixAAndMatrixBAreNullSouldReturnFalse() {
+        MatrixCalcMath math = new MatrixCalcMath();
+        Double[][] matrixA = null;
+        Double[][] matrixB = null;
+        assertFalse("Matrix A and B are null but detected as Linked", math.checkIfMatriciesAreLinked(matrixA, matrixB));
+    }
+
     @Test
-    public void shouldAlwaysBeTrue() {
-        //TODO replace this test through a real one!!
-        assertTrue("The JUnit setup is not correct, this test only assertTrue.", true);
+    public void MatrixAAndMatrixBAreNotLinkedSouldReturnFalse() {
+        MatrixCalcMath math = new MatrixCalcMath();
+        Double[][] matrixA = new Double[1][1];
+        Double[][] matrixB = new Double[2][1];
+        assertFalse("Matrix A and B are not Linked but detected as Linked",
+                math.checkIfMatriciesAreLinked(matrixA, matrixB));
     }
 }