diff --git a/src/main/java/com/thealgorithms/maths/LongDivision.java b/src/main/java/com/thealgorithms/maths/LongDivision.java
index 88a0a261..2578fe2e 100644
--- a/src/main/java/com/thealgorithms/maths/LongDivision.java
+++ b/src/main/java/com/thealgorithms/maths/LongDivision.java
@@ -11,6 +11,9 @@ public static int divide(int dividend, int divisor) {
         long new_dividend_1 = dividend;
         long new_divisor_1 = divisor;
 
+        if(divisor == 0){
+            return 0;
+        }
         if (dividend < 0) {
             new_dividend_1 = new_dividend_1 * -1;
         }
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java
new file mode 100644
index 00000000..2ed3b534
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java
@@ -0,0 +1,78 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class BinaryTreeTest {
+
+    //checks that adding populating the tree and searching for data
+    //retrieves the expected data
+@Test
+void test1(){
+    BinaryTree t = new BinaryTree();
+    t.put(3);
+    t.put(5);
+    t.put(7);
+    t.put(9);
+    t.put(12);
+    
+
+    assertEquals(t.find(5).data, 5);
+    assertEquals(t.find(7).data, 7);
+}
+
+    //checks that removing data from the tree
+    //properly removes and makes the new root the expected new root
+@Test
+void test2(){
+    BinaryTree t = new BinaryTree();
+    t.put(3);
+    t.put(5);
+    t.put(7);
+    t.put(9);
+    t.put(12);
+    t.remove(3);
+    t.remove(5);
+    t.remove(7);
+    
+
+    assertEquals(t.getRoot().data, 9);
+}
+
+//checks that removing an unexistend node returns false
+// as specified by the documentation of the function
+@Test
+void test3(){
+    BinaryTree t = new BinaryTree();
+    t.put(3);
+    t.put(5);
+    t.put(7);
+    t.put(9);
+    t.put(12);
+
+    assertEquals(t.remove(9), true);
+    assertEquals(t.remove(398745987), false);
+}
+
+//check if the bfs, inOrder, preOrder and postOrder functions
+//worg as expected, also increases the coverage measures in
+//JaCoCo
+@Test
+void test4(){
+    BinaryTree t = new BinaryTree();
+    t.put(3);
+    t.put(5);
+    t.put(7);
+    t.put(9);
+    t.put(12);
+
+    t.bfs(t.find(12));
+    t.inOrder(t.getRoot());
+    t.preOrder(t.getRoot());
+    t.postOrder(t.getRoot());
+
+    assertEquals(t.remove(9), true);
+    assertEquals(t.remove(398745987), false);
+}
+}
diff --git a/src/test/java/com/thealgorithms/maths/LongDivisionTest.java b/src/test/java/com/thealgorithms/maths/LongDivisionTest.java
index c35b606a..65ee328c 100644
--- a/src/test/java/com/thealgorithms/maths/LongDivisionTest.java
+++ b/src/test/java/com/thealgorithms/maths/LongDivisionTest.java
@@ -5,21 +5,51 @@ import org.junit.jupiter.api.Test;
 import static org.junit.jupiter.api.Assertions.*;
 
 public class LongDivisionTest {
-	
+
+    // Requirement: Dividend (positive) is  greater than divisor (positive), returns correct integer after division
     @Test
     void testOne() {
         assertEquals(3, LongDivision.divide(10,3));
     }
-  
-      @Test
+
+    // Requirement: Dividend (positive) is  greater than divisor (negative), returns correct integer after division
+    @Test
     void testTwo() {
         assertEquals(-2, LongDivision.divide(7,-3));
     }
   
-  
-      @Test
+    // Requirement: Dividend (positive) is  greater than divisor (negative), returns correct integer after division
+    // Basically the same as in the first test
+    @Test
     void testThree() {
         assertEquals(10, LongDivision.divide(105,10));
     }
+
+    // Requirement: Dividend (negative), divisor (positive), returns correct integer after division
+    // Tests the case where the dividend is less than 0.
+    @Test
+    void testNegativeDividend() {
+        assertEquals(-1, LongDivision.divide(-5,3));
+    }
 	
+    // Requirement: Dividend (positive), divisor (positive), returns correct integer after division
+    // Tests the case where the dividend is less than the divisor. The test should return 0 in this case. 
+    @Test
+    void testDividendLessThanDivisor() {
+        assertEquals(0, LongDivision.divide(3,5));
+    }
+
+    // Requirement: Dividend (neither), divisor (positive), returns correct integer after division
+    // Tests the case where the dividend is 0. This should return a 0.
+    @Test
+    void testDividendIsZero() {
+        assertEquals(0, LongDivision.divide(0,5));
+    }
+
+    // Requirement: Dividend (positive), divisor (neither), returns correct integer after division
+    // Tests the case where the divisor is 0. This should return a 0.
+    @Test
+    void testDivisionByZero() {
+        assertEquals(0, LongDivision.divide(5,0));  
+    }
 }
diff --git a/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java b/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java
new file mode 100644
index 00000000..906ab829
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java
@@ -0,0 +1,29 @@
+
+package com.thealgorithms.others;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class CRCAlgorithmTest {
+
+    @Test
+    void test1(){
+        CRCAlgorithm c = new CRCAlgorithm("10010101010100101010010000001010010101010", 10, 0.0);
+
+        //A bit-error rate of 0.0 should not provide any wrong messages
+        c.changeMess();
+        c.divideMessageWithP(false);
+        assertEquals(c.getWrongMess(), 0);
+    }
+
+    @Test
+    void test2(){
+        CRCAlgorithm c = new CRCAlgorithm("10010101010100101010010000001010010101010", 10, 1.0);
+
+        //A bit error rate of 1.0 should not provide any correct messages
+        c.changeMess();
+        c.divideMessageWithP(false);
+        assertEquals(c.getCorrectMess(), 0);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/MyAtoiTest.java b/src/test/java/com/thealgorithms/strings/MyAtoiTest.java
index ef092ab2..29dda8c0 100644
--- a/src/test/java/com/thealgorithms/strings/MyAtoiTest.java
+++ b/src/test/java/com/thealgorithms/strings/MyAtoiTest.java
@@ -11,15 +11,33 @@ public class MyAtoiTest {
         assertEquals(42, MyAtoi.myAtoi("42"));
     }
   
-      @Test
+    @Test
     void testTwo() {
         assertEquals(-42, MyAtoi.myAtoi("   -42"));
     }
   
-  
-      @Test
+    @Test
     void testThree() {
         assertEquals(4193, MyAtoi.myAtoi("4193 with words"));
     }
 	
+    @Test
+    void testFour() {
+        assertEquals(0, MyAtoi.myAtoi("0"));
+    }
+
+    @Test
+    void testFive() {
+        assertEquals(5678, MyAtoi.myAtoi("5678"));
+    }
+
+    @Test
+    void testSix() {
+        assertEquals(42, MyAtoi.myAtoi("+42"));
+    }
+
+    @Test
+    void testSeven() {
+        assertEquals(0, MyAtoi.myAtoi("  +0   "));
+    }
 }