Add tests, remove main in LowerBound (#5672)

src/test/java/com/thealgorithms/searches/LowerBoundTest.java

@@ -0,0 +1,59 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class LowerBoundTest {
+
+    /**
+     * Test finding the lower bound for an element present in the array.
+     */
+    @Test
+    void testLowerBoundElementPresent() {
+        Integer[] array = {1, 2, 3, 4, 5};
+        LowerBound lowerBound = new LowerBound();
+
+        // Test for a value that is present
+        assertEquals(2, lowerBound.find(array, 3), "Lower bound for 3 should be at index 2");
+        assertEquals(0, lowerBound.find(array, 1), "Lower bound for 1 should be at index 0");
+        assertEquals(4, lowerBound.find(array, 5), "Lower bound for 5 should be at index 4");
+    }
+
+    /**
+     * Test finding the lower bound for a value greater than the maximum element in the array.
+     */
+    @Test
+    void testLowerBoundElementGreaterThanMax() {
+        Integer[] array = {1, 2, 3, 4, 5};
+        LowerBound lowerBound = new LowerBound();
+
+        // Test for a value greater than the maximum
+        assertEquals(4, lowerBound.find(array, 6), "Lower bound for 6 should be at index 4");
+    }
+
+    /**
+     * Test finding the lower bound for a value less than the minimum element in the array.
+     */
+    @Test
+    void testLowerBoundElementLessThanMin() {
+        Integer[] array = {1, 2, 3, 4, 5};
+        LowerBound lowerBound = new LowerBound();
+
+        // Test for a value less than the minimum
+        assertEquals(0, lowerBound.find(array, 0), "Lower bound for 0 should be at index 0");
+    }
+
+    /**
+     * Test finding the lower bound for a non-existent value that falls between two elements.
+     */
+    @Test
+    void testLowerBoundNonExistentValue() {
+        Integer[] array = {1, 2, 3, 4, 5};
+        LowerBound lowerBound = new LowerBound();
+
+        // Test for a value that is not present
+        assertEquals(4, lowerBound.find(array, 7), "Lower bound for 7 should be at index 4");
+        assertEquals(0, lowerBound.find(array, 0), "Lower bound for 0 should be at index 0");
+    }
+}