diff --git a/tests/thread/thread_exc1.py b/tests/thread/thread_exc1.py
index 9ef3d2a154..10fb94b4fb 100644
--- a/tests/thread/thread_exc1.py
+++ b/tests/thread/thread_exc1.py
@@ -2,10 +2,6 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
-try:
-    import utime as time
-except ImportError:
-    import time
 import _thread
 
 def foo():
@@ -16,9 +12,19 @@ def thread_entry():
         foo()
     except ValueError:
         pass
+    with lock:
+        global n_finished
+        n_finished += 1
 
-for i in range(4):
+lock = _thread.allocate_lock()
+n_thread = 4
+n_finished = 0
+
+# spawn threads
+for i in range(n_thread):
     _thread.start_new_thread(thread_entry, ())
 
-time.sleep(0.2)
+# busy wait for threads to finish
+while n_finished < n_thread:
+    pass
 print('done')
diff --git a/tests/thread/thread_ident1.py b/tests/thread/thread_ident1.py
index f329566764..217fce73b1 100644
--- a/tests/thread/thread_ident1.py
+++ b/tests/thread/thread_ident1.py
@@ -2,20 +2,20 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
-try:
-    import utime as time
-except ImportError:
-    import time
 import _thread
 
 def thread_entry():
     tid = _thread.get_ident()
     print('thread', type(tid) == int, tid != 0, tid != tid_main)
+    global finished
+    finished = True
 
 tid_main = _thread.get_ident()
 print('main', type(tid_main) == int, tid_main != 0)
 
+finished = False
 _thread.start_new_thread(thread_entry, ())
 
-time.sleep(0.2)
+while not finished:
+    pass
 print('done')
diff --git a/tests/thread/thread_shared1.py b/tests/thread/thread_shared1.py
index 6ef4b654f8..13c6651cc4 100644
--- a/tests/thread/thread_shared1.py
+++ b/tests/thread/thread_shared1.py
@@ -2,10 +2,6 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
-try:
-    import utime as time
-except ImportError:
-    import time
 import _thread
 
 def foo(i):
@@ -14,11 +10,22 @@ def foo(i):
 def thread_entry(n, tup):
     for i in tup:
         foo(i)
+    with lock:
+        global n_finished
+        n_finished += 1
 
+lock = _thread.allocate_lock()
+n_thread = 2
+n_finished = 0
+
+# the shared data structure
 tup = (1, 2, 3, 4)
-_thread.start_new_thread(thread_entry, (100, tup))
-_thread.start_new_thread(thread_entry, (100, tup))
 
-# wait for threads to finish
-time.sleep(0.2)
+# spawn threads
+for i in range(n_thread):
+    _thread.start_new_thread(thread_entry, (100, tup))
+
+# busy wait for threads to finish
+while n_finished < n_thread:
+    pass
 print(tup)
diff --git a/tests/thread/thread_shared2.py b/tests/thread/thread_shared2.py
index 3e3e2dc33a..e4bfe78022 100644
--- a/tests/thread/thread_shared2.py
+++ b/tests/thread/thread_shared2.py
@@ -3,10 +3,6 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
-try:
-    import utime as time
-except ImportError:
-    import time
 import _thread
 
 def foo(lst, i):
@@ -15,11 +11,22 @@ def foo(lst, i):
 def thread_entry(n, lst, idx):
     for i in range(n):
         foo(lst, idx)
+    with lock:
+        global n_finished
+        n_finished += 1
 
+lock = _thread.allocate_lock()
+n_thread = 2
+n_finished = 0
+
+# the shared data structure
 lst = [0, 0]
-_thread.start_new_thread(thread_entry, (10, lst, 0))
-_thread.start_new_thread(thread_entry, (20, lst, 1))
 
-# wait for threads to finish
-time.sleep(0.2)
+# spawn threads
+for i in range(n_thread):
+    _thread.start_new_thread(thread_entry, ((i + 1) * 10, lst, i))
+
+# busy wait for threads to finish
+while n_finished < n_thread:
+    pass
 print(lst)
diff --git a/tests/thread/thread_stacksize1.py b/tests/thread/thread_stacksize1.py
index b0118843b6..e3e77fadaf 100644
--- a/tests/thread/thread_stacksize1.py
+++ b/tests/thread/thread_stacksize1.py
@@ -3,10 +3,6 @@
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
 import sys
-try:
-    import utime as time
-except ImportError:
-    import time
 import _thread
 
 # different implementations have different minimum sizes
@@ -20,6 +16,9 @@ def foo():
 
 def thread_entry():
     foo()
+    with lock:
+        global n_finished
+        n_finished += 1
 
 # test set/get of stack size
 print(_thread.stack_size())
@@ -27,10 +26,16 @@ print(_thread.stack_size(sz))
 print(_thread.stack_size() == sz)
 print(_thread.stack_size())
 
+lock = _thread.allocate_lock()
+n_thread = 2
+n_finished = 0
+
 # set stack size and spawn a few threads
 _thread.stack_size(sz)
-for i in range(2):
+for i in range(n_thread):
     _thread.start_new_thread(thread_entry, ())
 
-time.sleep(0.2)
+# busy wait for threads to finish
+while n_finished < n_thread:
+    pass
 print('done')
diff --git a/tests/thread/thread_stress_recurse.py b/tests/thread/thread_stress_recurse.py
index eb9c136f25..68367c4dd7 100644
--- a/tests/thread/thread_stress_recurse.py
+++ b/tests/thread/thread_stress_recurse.py
@@ -2,10 +2,6 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
-try:
-    import utime as time
-except ImportError:
-    import time
 import _thread
 
 def foo():
@@ -16,8 +12,14 @@ def thread_entry():
         foo()
     except RuntimeError:
         print('RuntimeError')
+    global finished
+    finished = True
+
+finished = False
 
 _thread.start_new_thread(thread_entry, ())
 
-time.sleep(0.2)
+# busy wait for thread to finish
+while not finished:
+    pass
 print('done')