diff --git a/Makefile b/Makefile
index 91ccd67..ef5d3e2 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,7 @@ TARGET_EXECS := tests/test1 tests/copy_to_external_simple tests/copy_to_external
 vpath # clears VPATH
 vpath %.h $(INCLUDE_DIRS)
 
-LDFLAGS += -pthread -fsanitize=thread
+LDFLAGS += -pthread
 
 CFLAGS = -std=c11 -D_POSIX_C_SOURCE=200809L
 CFLAGS += $(INCLUDES)
diff --git a/tests/threads_read_same_file.c b/tests/threads_read_same_file.c
index a66d3d8..3eef91d 100644
--- a/tests/threads_read_same_file.c
+++ b/tests/threads_read_same_file.c
@@ -3,11 +3,15 @@
 #include <pthread.h>
 #include <string.h>
 
+#define LEN 1555
+#define BUFFER_SIZE 4000
+#define THREADS 20
+
 void *function(void *istr) {
 
     char *str = (char *)istr;
     char *path = "/f1";
-    char buffer[4000];
+    char buffer[BUFFER_SIZE];
 
     int f;
     ssize_t r;
@@ -32,7 +36,7 @@ void *function(void *istr) {
 }
 
 int main() {
-    char *str = (char *)malloc(sizeof(char) * 1555);
+    char str[LEN];
     memset(str, 'A', 1555);
     char *path = "/f1";
 
@@ -45,11 +49,11 @@ int main() {
 
     r = tfs_write(f, str, strlen(str));
     assert(r == strlen(str));
-    pthread_t tid[20];
-    for (int i = 0; i < 20; i++) {
+    pthread_t tid[THREADS];
+    for (int i = 0; i < THREADS; i++) {
         pthread_create(&tid[i], NULL, &function, str);
     }
-    for (int i = 0; i < 20; i++) {
+    for (int i = 0; i < THREADS; i++) {
         pthread_join(tid[i], NULL);
     }
     printf("Successful test.\n");
diff --git a/tests/threads_truncate_and_append.c b/tests/threads_truncate_and_append.c
index c3cb3b8..b5305c7 100644
--- a/tests/threads_truncate_and_append.c
+++ b/tests/threads_truncate_and_append.c
@@ -4,11 +4,12 @@
 #include <string.h>
 
 #define LEN 1555
+#define THREADS 19
 
 void *truncate(void *ipath) {
 
     char str[LEN];
-    memset(str, 'A', LEN);
+    memset(str, 'C', LEN);
     char *path = (char *)ipath;
 
     int f;
@@ -28,7 +29,7 @@ void *truncate(void *ipath) {
 void *append(void *ipath) {
 
     char str[LEN];
-    memset(str, 'A', LEN);
+    memset(str, 'B', LEN);
     char *path = (char *)ipath;
 
     int f;
@@ -48,44 +49,58 @@ void *append(void *ipath) {
 void write_to_file(char *path, char *contents) {
     int f = tfs_open(path, TFS_O_CREAT);
     assert(f != -1);
-    ssize_t r = tfs_write(f, contents, strlen(contents));
-    assert(r == strlen(contents));
+    ssize_t r = tfs_write(f, contents, LEN);
+    assert(r == LEN);
     assert(tfs_close(f) != -1);
 }
 
 int main() {
-    char *path_append = "/append.txt";
-    char *path_trunc = "/trunc.txt";
-    char str[LEN];
-    memset(str, 'A', LEN);
+    char path[THREADS][10];
+    char strA[LEN];
+    memset(strA, 'A', LEN);
+    char strB[LEN];
+    memset(strB, 'B', LEN);
+    char strC[LEN];
+    memset(strC, 'C', LEN);
     assert(tfs_init() != -1);
-
-    write_to_file(path_append, str);
-    write_to_file(path_trunc, str);
-
-    pthread_t tid[19];
-    for (int i = 0; i < 19; i++) {
-        if (i % 2 == 0)
-            pthread_create(&tid[i], NULL, &append, (void *)path_append);
-        else
-            pthread_create(&tid[i], NULL, &truncate, (void *)path_trunc);
+    for (int i = 0; i < THREADS; i++) {
+        sprintf(path[i], "/%d.txt", i);
+        write_to_file(path[i], strA);
     }
-    for (int i = 0; i < 19; i++) {
-        pthread_join(tid[i], NULL);
+    pthread_t tid[THREADS];
+    for (int i = 0; i < THREADS; i++) {
+        if (i % 2 == 0) {
+            pthread_create(&tid[i], NULL, &append, (void *)path[i]);
+        } else {
+            pthread_create(&tid[i], NULL, &truncate, (void *)path[i]);
+        }
     }
 
-    // TODO: check
-
-    /*f = tfs_open(path, 0);
-    assert(f != -1);
-
-    r = tfs_read(f, buffer, sizeof(buffer) - 1);
-    assert(r == strlen(str));
+    for (int i = 0; i < THREADS; i++) {
+        pthread_join(tid[i], NULL);
 
-    buffer[r] = '\0';
-    assert(strcmp(buffer, str) == 0);
+        int f = tfs_open(path[i], 0);
+        assert(f != -1);
+
+        char tmp[LEN];
+        if (i % 2 == 0) {
+            // append
+            assert(tfs_read(f, tmp, LEN) == LEN);
+            assert(memcmp(strA, tmp, LEN) == 0);
+            assert(tfs_read(f, tmp, LEN) == LEN);
+            assert(memcmp(strB, tmp, LEN) == 0);
+            assert(tfs_read(f, tmp, LEN) == 0);
+        } else {
+            // truncate
+            assert(tfs_read(f, tmp, LEN) == LEN);
+            assert(memcmp(strC, tmp, LEN) == 0);
+
+            assert(tfs_read(f, tmp, LEN) == 0);
+        }
+        assert(tfs_close(f) == 0);
+    }
 
-    assert(tfs_close(f) != -1);*/
+    assert(tfs_destroy() == 0);
 
     printf("Successful test.\n");
     return 0;
diff --git a/tests/threads_write_different_files.c b/tests/threads_write_different_files.c
index c77cf76..9e65796 100644
--- a/tests/threads_write_different_files.c
+++ b/tests/threads_write_different_files.c
@@ -24,6 +24,8 @@ void *function(void *ipath) {
 
     assert(tfs_close(f) != -1);
 
+    free(str);
+
     pthread_exit(NULL);
 }
 
@@ -49,6 +51,8 @@ void *function2(void *ipath) {
 
     assert(tfs_close(f) != -1);
 
+    free(str);
+
     pthread_exit(NULL);
 }
 
diff --git a/tests/threads_write_same_file.c b/tests/threads_write_same_file.c
index 3471810..705e5f2 100644
--- a/tests/threads_write_same_file.c
+++ b/tests/threads_write_same_file.c
@@ -20,6 +20,8 @@ void *function(void *ipath) {
 
     assert(tfs_close(f) != -1);
 
+    free(str);
+
     pthread_exit(NULL);
 }
 
@@ -58,6 +60,8 @@ int main() {
 
     assert(tfs_close(f) != -1);
 
+    free(str);
+
     printf("Successful test.\n");
     return 0;
 }
\ No newline at end of file