Beispiel TDD

pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>de.edu.hsfulda.ciip</groupId>
+  <artifactId>tdd-pure-function</artifactId>
+  <version>0.1.0-SNAPSHOT</version>
+    <properties>
+        <maven.compiler.target>11</maven.compiler.target>
+        <maven.compiler.source>11</maven.compiler.source>
+    </properties> 
+    <dependencies>
+      	<dependency> 
+		    <groupId>org.junit.jupiter</groupId>
+		    <artifactId>junit-jupiter-engine</artifactId>
+		    <version>5.5.2</version>
+      		<scope>test</scope>
+      	</dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>1.5.2</version>
+            <scope>test</scope>
+        </dependency>
+   </dependencies>
+</project>

src/main/java/de/edu/hsfulda/ccip/tdd/purefunction/BowlingCalculator.java

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+package de.edu.hsfulda.ccip.tdd.purefunction;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class BowlingCalculator {
+	@FunctionalInterface
+	interface FrameScorer {
+		int score(Matcher frameMatcher);
+	}
+
+	private static final int INITIAL_SCORE = 0;
+	private static final Pattern SINGLE_ROLL_PATTERN = Pattern.compile("\\d");
+	private static final Pattern SPARE_PATTERN = Pattern.compile("(\\d)/ ([-\\d])");
+
+	public int score(String rolls) {
+		int score = INITIAL_SCORE;
+		Matcher singleRollMatcher = SINGLE_ROLL_PATTERN.matcher(rolls);
+		score = scoreFrameType(score, singleRollMatcher, matcher -> Integer.parseInt(singleRollMatcher.group()));
+
+		Matcher spareMatcher = SPARE_PATTERN.matcher(rolls);
+		score = scoreFrameType(score, spareMatcher, matcher -> scoreSpareFrame(spareMatcher));
+
+		return score;
+	}
+
+	private int scoreSpareFrame(Matcher spareMatcher) {
+		int frameScore = 10 - Integer.parseInt(spareMatcher.group(1));
+		String nextRoll = spareMatcher.group(2);
+		if(!"-".equalsIgnoreCase(nextRoll)) {
+			frameScore += Integer.parseInt(spareMatcher.group(1));
+		}
+		return frameScore;
+	}
+
+	private int scoreFrameType(int score, Matcher scoreMatcher, FrameScorer frameScorer) {
+		while (scoreMatcher.find()) {
+			score += frameScorer.score(scoreMatcher);
+		}
+		return score;
+	}
+
+}

src/test/java/de/edu/hsfulda/ccip/tdd/purefunction/BowlingCalculatorTest.java

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+package de.edu.hsfulda.ccip.tdd.purefunction;
+
+import static org.junit.Assert.assertThat;
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.hamcrest.CoreMatchers;
+import org.junit.Assert;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class BowlingCalculatorTest {
+
+	private BowlingCalculator bowlingCalculator;
+
+	@BeforeEach
+	void setUp() throws Exception {
+		bowlingCalculator = new BowlingCalculator();
+	}
+
+	@Test
+	void resultOfWorstGameIsZero() {
+		// arrange
+		String rolls = "-- -- -- -- -- -- -- -- -- --";
+		int expectedScore = 0;
+		// act
+		int score = bowlingCalculator.score(rolls);
+		// assert
+		assertThat("score", score, CoreMatchers.equalTo(expectedScore));
+	}
+
+	@Test
+	void addUpSingleRollInIncompleteFrames() {
+		// arrange
+		String rolls = "-1 23 -4 5- -6 -7 8- 9- -- --";
+		int expectedScore = 45;
+		// act
+		int score = bowlingCalculator.score(rolls);
+		// assert
+		assertThat("score", score, CoreMatchers.equalTo(expectedScore));
+	}
+
+	@Test
+	void frameWithSpareCounts10() {
+		// arrange
+		String rolls = "-- -- 3/ -- 7/ -- -- -- -- --";
+		int expectedScore = 20;
+		// act
+		int score = bowlingCalculator.score(rolls);
+		// assert
+		assertThat("score", score, CoreMatchers.equalTo(expectedScore));
+	}
+	@Test
+	void frameWithSpareAddsNextRollTwice() {
+		// arrange
+		String rolls = "-- -- 3/ 2- 7/ 8- -- -- -- --";
+		int expectedScore = 40;
+		// act
+		int score = bowlingCalculator.score(rolls);
+		// assert
+		assertThat("score", score, CoreMatchers.equalTo(expectedScore));
+	}
+}