refactoring: removed magic numbers

fh.fd.ci.client/src/main/java/de/fd/fh/FigureBishop.java

@@ -5,7 +5,7 @@ public class FigureBishop extends Figure
     @Override
     public boolean moveAllowed(int src, int dst, Figure[] field)
     {
-        if ((dst-src) % 8 == 0) // nach oben/unten nicht erlaubt
+        if ((dst-src) % Figure.fieldLength == 0) // nach oben/unten nicht erlaubt
         {
             return false;
         }

fh.fd.ci.client/src/test/java/de/fd/fh/FigureBishopTest.java

@@ -7,10 +7,14 @@ import static org.junit.jupiter.api.Assertions.*;
 class FigureBishopTest
 {
     @Test
-    void checkInvalidMovesBishop()
+    void checkInvalidMovesBishopUpward()
     {
         Figure f = new FigureBishop();
 
-        assertFalse(f.moveAllowed(45, 37, new Figure[64]));
+        int src = Figure.fieldLength * 5 + 5;
+        int dst = src - Figure.fieldLength;
+
+        assertFalse(f.moveAllowed(src, dst,
+                new Figure[Figure.fieldLength * Figure.fieldLength]));
     }
 }