diff --git a/src/test/java/org/apache/commons/text/similarity/EditDistanceFromTest.java b/src/test/java/org/apache/commons/text/similarity/EditDistanceFromTest.java
new file mode 100644
index 0000000000..32d85752aa
--- /dev/null
+++ b/src/test/java/org/apache/commons/text/similarity/EditDistanceFromTest.java
@@ -0,0 +1,45 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.text.similarity;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class EditDistanceFromTest {
+
+    private LongestCommonSubsequenceDistance longestCommonSubsequenceDistance;
+    private EditDistanceFrom<Integer> editDistanceFrom;
+
+    @BeforeEach
+    void doBeforeEachTest() {
+        longestCommonSubsequenceDistance = new LongestCommonSubsequenceDistance();
+        editDistanceFrom = new EditDistanceFrom<>(longestCommonSubsequenceDistance, "asdf");
+    }
+
+    @Test
+    void testGetLeft() {
+        assertEquals("asdf", editDistanceFrom.getLeft());
+    }
+
+    @Test
+    void testGetSimilarityScore() {
+        assertEquals(longestCommonSubsequenceDistance, editDistanceFrom.getEditDistance());
+    }
+
+}
diff --git a/src/test/java/org/apache/commons/text/similarity/JaccardSimilarityTest.java b/src/test/java/org/apache/commons/text/similarity/JaccardSimilarityTest.java
index 334ea748fc..f7ef2ab75f 100644
--- a/src/test/java/org/apache/commons/text/similarity/JaccardSimilarityTest.java
+++ b/src/test/java/org/apache/commons/text/similarity/JaccardSimilarityTest.java
@@ -89,4 +89,14 @@ void testGettingJaccardSimilarityNullString() {
     void testGettingJaccardSimilarityStringNull() {
         assertThrows(IllegalArgumentException.class, () -> classBeingTested.apply(" ", null));
     }
+
+    @Test
+    void testGettingJaccardSimilarityNullSimilarityInput() {
+        assertThrows(IllegalArgumentException.class, () -> classBeingTested.apply(null, new SimilarityCharacterInput("asdf")));
+    }
+
+    @Test
+    void testGettingJaccardSimilaritySimilarityInputNull() {
+        assertThrows(IllegalArgumentException.class, () -> classBeingTested.apply(new SimilarityCharacterInput("asdf"), null));
+    }
 }
diff --git a/src/test/java/org/apache/commons/text/similarity/JaroWinklerDistanceTest.java b/src/test/java/org/apache/commons/text/similarity/JaroWinklerDistanceTest.java
index 509d58bb59..7df3a10338 100644
--- a/src/test/java/org/apache/commons/text/similarity/JaroWinklerDistanceTest.java
+++ b/src/test/java/org/apache/commons/text/similarity/JaroWinklerDistanceTest.java
@@ -18,6 +18,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -105,4 +106,9 @@ void testGetJaroWinklerDistance_StringString() {
         assertEquals(1 - 0.51111d, distance.apply("foo", "  foo"), 0.00001d);
     }
 
+    @Test
+    void testMatches() {
+        assertArrayEquals(new int[]{2, 0, 2}, distance.matches("ab", "aba"));
+    }
+
 }
diff --git a/src/test/java/org/apache/commons/text/similarity/LevenshteinDetailedDistanceTest.java b/src/test/java/org/apache/commons/text/similarity/LevenshteinDetailedDistanceTest.java
index 9ba1baf753..f80cbc7915 100644
--- a/src/test/java/org/apache/commons/text/similarity/LevenshteinDetailedDistanceTest.java
+++ b/src/test/java/org/apache/commons/text/similarity/LevenshteinDetailedDistanceTest.java
@@ -41,6 +41,14 @@ void testApplyThrowsIllegalArgumentExceptionAndCreatesLevenshteinDetailedDistanc
     void testApplyWithNullSimilarityInput() {
         assertThrows(IllegalArgumentException.class,
                 () -> new LevenshteinDetailedDistance(0).apply((SimilarityInput<Object>) null, (SimilarityInput<Object>) null));
+        assertThrows(IllegalArgumentException.class,
+                () -> new LevenshteinDetailedDistance(0).apply(new SimilarityCharacterInput("asdf"), (SimilarityCharacterInput) null));
+        assertThrows(IllegalArgumentException.class,
+                () -> new LevenshteinDetailedDistance(0).apply((SimilarityCharacterInput) null, new SimilarityCharacterInput("asdf")));
+        assertThrows(IllegalArgumentException.class,
+                () -> new LevenshteinDetailedDistance(null).apply(new SimilarityCharacterInput("asdf"), (SimilarityCharacterInput) null));
+        assertThrows(IllegalArgumentException.class,
+                () -> new LevenshteinDetailedDistance(null).apply((SimilarityCharacterInput) null, new SimilarityCharacterInput("asdf")));
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/text/similarity/LevenshteinDistanceTest.java b/src/test/java/org/apache/commons/text/similarity/LevenshteinDistanceTest.java
index 99dd5e72b5..8aa3960d72 100644
--- a/src/test/java/org/apache/commons/text/similarity/LevenshteinDistanceTest.java
+++ b/src/test/java/org/apache/commons/text/similarity/LevenshteinDistanceTest.java
@@ -34,6 +34,10 @@ class LevenshteinDistanceTest {
     @Test
     void testApplyThrowsIllegalArgumentExceptionSimilarityInput() {
         assertThrows(IllegalArgumentException.class, () -> new LevenshteinDistance(0).apply((SimilarityInput<Object>) null, (SimilarityInput<Object>) null));
+        assertThrows(IllegalArgumentException.class, () -> new LevenshteinDistance(0).apply(new SimilarityCharacterInput("asdf"),
+                (SimilarityCharacterInput) null));
+        assertThrows(IllegalArgumentException.class, () -> new LevenshteinDistance(0).apply((SimilarityCharacterInput) null,
+                new SimilarityCharacterInput("asdf")));
     }
 
     @Test
@@ -85,6 +89,12 @@ void testGetLevenshteinDistance_StringNullInt(final Class<?> cls) {
         assertThrows(IllegalArgumentException.class, () -> UNLIMITED_DISTANCE.apply(SimilarityInputTest.build(cls, "a"), SimilarityInputTest.build(cls, null)));
     }
 
+    @Test
+    void testGetLevenshteinDistance_EmptyStringString() {
+        assertEquals(-1, new LevenshteinDistance(0).apply(new SimilarityCharacterInput(""),
+                new SimilarityCharacterInput("asdf")));
+    }
+
     @ParameterizedTest
     @MethodSource("org.apache.commons.text.similarity.SimilarityInputTest#similarityInputs()")
     void testGetLevenshteinDistance_StringString(final Class<?> cls) {
diff --git a/src/test/java/org/apache/commons/text/similarity/LongestCommonSubsequenceTest.java b/src/test/java/org/apache/commons/text/similarity/LongestCommonSubsequenceTest.java
index b280361a1f..e5208a2011 100644
--- a/src/test/java/org/apache/commons/text/similarity/LongestCommonSubsequenceTest.java
+++ b/src/test/java/org/apache/commons/text/similarity/LongestCommonSubsequenceTest.java
@@ -18,6 +18,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -133,4 +134,10 @@ void testLongestCommonSubsequenceApply() {
         assertEquals(4, subject.apply("leettteft", "ritttght"));
         assertEquals(15, subject.apply("the same string", "the same string"));
     }
+
+    @Test
+    void testLongestCommonSubstringLengthArray() {
+        assertArrayEquals(new int[][]{ {0, 0, 0, 0}, {0, 1, 1, 1}, {0, 1, 2, 2}}, subject.longestCommonSubstringLengthArray("ab", "abc"));
+    }
+
 }
diff --git a/src/test/java/org/apache/commons/text/similarity/SimilarityScoreFromTest.java b/src/test/java/org/apache/commons/text/similarity/SimilarityScoreFromTest.java
index 9f141f7e4e..cd037b4dc5 100644
--- a/src/test/java/org/apache/commons/text/similarity/SimilarityScoreFromTest.java
+++ b/src/test/java/org/apache/commons/text/similarity/SimilarityScoreFromTest.java
@@ -20,17 +20,35 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 class SimilarityScoreFromTest {
 
+    private LongestCommonSubsequence longestCommonSubsequence;
+    private SimilarityScoreFrom<Integer> similarityScoreFrom;
+
+    @BeforeEach
+    void doBeforeEachTest() {
+        longestCommonSubsequence = new LongestCommonSubsequence();
+        similarityScoreFrom = new SimilarityScoreFrom<>(longestCommonSubsequence, "asdf");
+    }
+
     @Test
     void testApply() {
-        final LongestCommonSubsequence longestCommonSubsequence = new LongestCommonSubsequence();
-        final SimilarityScoreFrom<Integer> similarityScoreFrom = new SimilarityScoreFrom<>(longestCommonSubsequence, "asdf");
         assertEquals(1, similarityScoreFrom.apply("s"));
     }
 
+    @Test
+    void testGetLeft() {
+        assertEquals("asdf", similarityScoreFrom.getLeft());
+    }
+
+    @Test
+    void testGetSimilarityScore() {
+        assertEquals(longestCommonSubsequence, similarityScoreFrom.getSimilarityScore());
+    }
+
     @Test
     void testFailsToCreateSimilarityScoreFromThrowsIllegalArgumentException() {
         assertThrows(IllegalArgumentException.class, () -> new SimilarityScoreFrom<>(null, ""));