diff --git a/.gitignore b/.gitignore
index 496ee2c..5b800ea 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,4 @@
-.DS_Store
\ No newline at end of file
+.DS_Store
+
+tests/build/
+build/
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..e516763
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,15 @@
+cmake_minimum_required(VERSION 3.16)
+project(tests LANGUAGES C)
+
+enable_testing()
+
+add_executable(test_vector
+    tests/test_vector.c
+)
+
+add_executable(test_set
+    tests/test_set.c
+)
+
+add_test(NAME test_vector COMMAND test_vector)
+add_test(NAME test_set COMMAND test_set)
\ No newline at end of file
diff --git a/README.md b/README.md
index 87c14d5..4602abd 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,8 @@ Literally just copy the header file you want and let your favourite semi-usable
 
 ## Contributing
 If you want to contribute, please make a pull request and I'll review it. If you want to contribute a new type or function, please make sure it is useful and not just a "cool" thing.
+If you change an existing type, please run **make** in *build/* directory and **ctest** to ensure compatibility hasn't been broken.
+If it's new, please write a **test** for it in *tests/test_<name>.c* so others can see the guidelines on how the type is used.
 
 ## Legal Mumbo Jumbo
 Licensed under the MIT License (because GPL doesn't make sense for this (sorry Stallman))
diff --git a/tests/test_set.c b/tests/test_set.c
new file mode 100644
index 0000000..9039869
--- /dev/null
+++ b/tests/test_set.c
@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include "../set.h"
+
+int main(void) {
+    set_t* set = set_create(sizeof(int));
+    if (!set) {
+        fprintf(stderr, "Failed to create set\n");
+        return 1;
+    }
+
+    for (int i = 0; i < 10; ++i) {
+        if (set_insert(set, &i) != 0) {
+            fprintf(stderr, "Failed to insert %d\n", i);
+            set_destroy(&set);
+            return 1;
+        }
+    }
+
+    for (size_t i = 0; i < set_size(set); ++i) {
+        int* value = (int*)set_get_const(set, i);
+        if (value) {
+            printf("set[%zu] = %d\n", i, *value);
+        } else {
+            fprintf(stderr, "Failed to get value at index %zu\n", i);
+        }
+    }
+
+    set_destroy(&set);
+    if (set != NULL) {
+        fprintf(stderr, "Set pointer was not set to NULL after destruction\n");
+        return 1;
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/tests/test_vector.c b/tests/test_vector.c
new file mode 100644
index 0000000..f5ed596
--- /dev/null
+++ b/tests/test_vector.c
@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include "../vector.h"
+
+int main(void) {
+    vector_t* vec = vector_create(sizeof(int));
+    if (!vec) {
+        fprintf(stderr, "Failed to create vector\n");
+        return 1;
+    }
+
+    for (int i = 0; i < 10; ++i) {
+        if (vector_push_back(vec, &i) != 0) {
+            fprintf(stderr, "Failed to push back %d\n", i);
+            vector_destroy(&vec);
+            return 1;
+        }
+    }
+
+    for (size_t i = 0; i < vector_size(vec); ++i) {
+        int* value = (int*)vector_get(vec, i);
+        if (value) {
+            printf("vec[%zu] = %d\n", i, *value);
+        } else {
+            fprintf(stderr, "Failed to get value at index %zu\n", i);
+        }
+    }
+
+    vector_destroy(&vec);
+    if (vec != NULL) {
+        fprintf(stderr, "Vector pointer was not set to NULL after destruction\n");
+        return 1;
+    }
+    return 0;
+}
\ No newline at end of file