Add test for Tichu.

app/src/test/java/me/zobrist/tichucounter/TichuUnitTest.kt

@@ -0,0 +1,62 @@
+package me.zobrist.tichucounter
+
+import me.zobrist.tichucounter.domain.Round
+import me.zobrist.tichucounter.domain.Tichu
+import org.junit.Assert.*
+import org.junit.Test
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+class TichuUnitTest {
+    @Test
+    fun calculation_isCorrect() {
+
+        var inputScoreA = 125
+        var inputScoreB = -25
+
+        val tichu: Tichu = Tichu()
+
+        // Normal round range -25 to 125 as input
+        while (inputScoreB <= 125) {
+            assertGeneratedRound(tichu, inputScoreA, inputScoreB)
+
+            inputScoreA -= 5
+            inputScoreB += 5
+        }
+
+        // Double win
+        assertGeneratedRound(tichu, 200, 0)
+
+        // Double win with Tichu
+        assertGeneratedRound(tichu, 300, 0)
+
+        // Double win with Grand Tichu
+        assertGeneratedRound(tichu, 400, 0)
+
+        //Good rounds trough Tichu
+        assertValidRound(tichu, Round(0,0))
+        assertValidRound(tichu, Round(-100,0))
+
+        //Bad rounds
+        assertInvalidRound(tichu, Round(5, 12))
+        assertInvalidRound(tichu, Round(12, 5))
+        assertInvalidRound(tichu, Round(5, 55))
+    }
+
+    private fun assertGeneratedRound(tichu: Tichu, scoreA: Int, expectedScoreB: Int) {
+        val round = Round(scoreA, tichu.calculateOtherScore(scoreA))
+        assertEquals(expectedScoreB, round.scoreB)
+        assertTrue(tichu.isValidRound(round))
+    }
+
+    private fun assertInvalidRound(tichu: Tichu, round: Round) {
+        assertFalse(tichu.isValidRound(round))
+    }
+
+    private fun assertValidRound(tichu: Tichu, round: Round) {
+        assertTrue(tichu.isValidRound(round))
+    }
+}