add test case 1

Author: dbc2201

.idea/workspace.xml

@@ -1,10 +1,11 @@
 package io.github.dbc;
 
-import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 class DuplicateCharactersCounterTest {
     private DuplicateCharactersCounter counter;
 
@@ -14,8 +15,15 @@ void setUp() {
     }
 
     @Test
-    @DisplayName("")
-    void countDuplicateCharacters() {
-        Assertions.fail();
+    @DisplayName("should return count as 1 for all non duplicate characters")
+    void shouldReturnCount1ForNonDuplicateCharacters() {
+        // Arrange
+        String input = "abcdefghijklmnopqrstuvwxyz";
+        // Act
+        var characterIntegerMap = counter.countDuplicateCharacters(input);
+        // get the value for key 'a'
+        var count = characterIntegerMap.get('a');
+        // Assert
+        assertEquals(1, count, "the count value for all non duplicate characters should be 1");
     }
 }