diff --git a/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/subscription/exception/NotValidSubscriptionExceptionTest.java b/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/subscription/exception/NotValidSubscriptionExceptionTest.java
new file mode 100644
index 0000000..086ac8e
--- /dev/null
+++ b/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/subscription/exception/NotValidSubscriptionExceptionTest.java
@@ -0,0 +1,60 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.subscription.exception;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class NotValidSubscriptionExceptionTest {
+
+    @Test
+    @DisplayName("Exception should be created with the provided message")
+    void testExceptionCreation() {
+        String errorMessage = "Subscription data is not valid";
+
+        NotValidSubscriptionException exception = new NotValidSubscriptionException(errorMessage);
+
+        assertEquals(errorMessage, exception.getMessage());
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {
+            "Customer ID cannot be null",
+            "Duration is not valid",
+            "Payment Method cannot be blank"
+    })
+    @DisplayName("Exception should handle different validation messages")
+    void testExceptionWithDifferentMessages(String errorMessage) {
+        NotValidSubscriptionException exception = new NotValidSubscriptionException(errorMessage);
+
+        assertEquals(errorMessage, exception.getMessage());
+    }
+
+    @Test
+    @DisplayName("Exception should be properly thrown and caught")
+    void testExceptionCanBeThrownAndCaught() {
+        String errorMessage = "Required field is missing";
+
+        Exception exception = assertThrows(NotValidSubscriptionException.class, () -> {
+            throw new NotValidSubscriptionException(errorMessage);
+        });
+
+        assertEquals(errorMessage, exception.getMessage());
+    }
+
+    @Test
+    @DisplayName("Exception should be catchable as a general Exception")
+    void testExceptionInheritance() {
+        String errorMessage = "Invalid subscription data";
+
+        try {
+            throw new NotValidSubscriptionException(errorMessage);
+        } catch (Exception e) {
+            assertEquals(NotValidSubscriptionException.class, e.getClass());
+            assertEquals(errorMessage, e.getMessage());
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/subscription/exception/SubscriptionNotFoundExceptionTest.java b/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/subscription/exception/SubscriptionNotFoundExceptionTest.java
new file mode 100644
index 0000000..66f8f7a
--- /dev/null
+++ b/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/subscription/exception/SubscriptionNotFoundExceptionTest.java
@@ -0,0 +1,52 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.subscription.exception;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.customer.exception.CustomerNotFoundException;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.UUID;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+
+public class SubscriptionNotFoundExceptionTest {
+
+    @Test
+    @DisplayName("Exception message should contain the UUID provided")
+    void testExceptionMessageContainsUUID() {
+        UUID uuid = UUID.randomUUID();
+
+        SubscriptionNotFoundException exception = new SubscriptionNotFoundException(uuid);
+
+        String expectedMessage = String.format("The subscription with id %s does not exist", uuid);
+        assertEquals(expectedMessage, exception.getMessage());
+    }
+
+    @Test
+    @DisplayName("Exception should use the correct constant message format")
+    void testExceptionUsesConstantMessageFormat() {
+        UUID uuid = UUID.randomUUID();
+
+        SubscriptionNotFoundException exception = new SubscriptionNotFoundException(uuid);
+
+        String expectedFormatWithPlaceholder = "The subscription with id {0} does not exist";
+        assertEquals(SubscriptionNotFoundException.THE_SUBSCRIPTION_WITH_ID_DOES_NOT_EXIST_MESSAGE,
+                expectedFormatWithPlaceholder);
+        assertTrue(exception.getMessage().contains(uuid.toString()));
+    }
+
+    @Test
+    @DisplayName("Exception should be properly thrown and caught")
+    void testExceptionCanBeThrownAndCaught() {
+        UUID uuid = UUID.randomUUID();
+
+        try {
+            throw new SubscriptionNotFoundException(uuid);
+        } catch (SubscriptionNotFoundException e) {
+            String expectedMessage = String.format("The subscription with id %s does not exist", uuid);
+            assertEquals(expectedMessage, e.getMessage());
+        }
+    }
+
+}