gs-cv: LetterPairSimilarity: added a test class and checked for null/…

…empty strings
genericsystem · Oct 12, 2017 · 9b8b548 · 9b8b548
1 parent a38f958
commit 9b8b548
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diff --git a/gs-cv/src/main/java/org/genericsystem/cv/utils/LetterPairSimilarity.java b/gs-cv/src/main/java/org/genericsystem/cv/utils/LetterPairSimilarity.java
@@ -15,6 +15,15 @@ public static void main(String[] args) {
 	}
 
 	public static double compareStrings(String string1, String string2) {
+		if (null == string1 || null == string2)
+			throw new IllegalArgumentException("LetterPairSimilarity requires two not null strings");
+		if (string1.equals(string2))
+			return 1d;
+		if (string1.isEmpty())
+			return 0;
+		if (string2.isEmpty())
+			return 0;
+
 		List<String> pairs1 = wordLetterPairs(string1.toLowerCase());
 		List<String> pairs2 = wordLetterPairs(string2.toLowerCase());
 		int intersection = 0;

diff --git a/gs-cv/src/test/java/org/genericsystem/cv/utils/LetterPairSimilarityTest.java b/gs-cv/src/test/java/org/genericsystem/cv/utils/LetterPairSimilarityTest.java
@@ -0,0 +1,33 @@
+package org.genericsystem.cv.utils;
+
+import static org.testng.Assert.assertEquals;
+
+import org.testng.annotations.Test;
+
+public class LetterPairSimilarityTest {
+
+	@Test
+	public void compareStrings() {
+		String ref = "healed";
+		assertEquals(LetterPairSimilarity.compareStrings("", ""), 1d, 0.0);
+		assertEquals(LetterPairSimilarity.compareStrings("kitten", ""), 0, 0.0);
+		assertEquals(LetterPairSimilarity.compareStrings("", "kitten"), 0, 0.0);
+		assertEquals(LetterPairSimilarity.compareStrings(ref, ref), 1d, 0.0);
+		assertEquals(LetterPairSimilarity.compareStrings(ref, "sealed"), 0.800, 0.001);
+		assertEquals(LetterPairSimilarity.compareStrings(ref, "healthy"), 0.545, 0.001);
+		assertEquals(LetterPairSimilarity.compareStrings(ref, "heard"), 0.444, 0.001);
+		assertEquals(LetterPairSimilarity.compareStrings(ref, "herded"), 0.400, 0.001);
+		assertEquals(LetterPairSimilarity.compareStrings(ref, "help"), 0.250, 0.001);
+		assertEquals(LetterPairSimilarity.compareStrings(ref, "sold"), 0, 0.001);
+	}
+
+	@Test(expectedExceptions = IllegalArgumentException.class)
+	public void compareStringsNullString() {
+		LetterPairSimilarity.compareStrings("kitten", null);
+	}
+
+	@Test(expectedExceptions = IllegalArgumentException.class)
+	public void compareStringsNullString2() {
+		LetterPairSimilarity.compareStrings(null, "kitten");
+	}
+}