diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/context.py b/tests/context.py
new file mode 100644
index 0000000..7ae38a1
--- /dev/null
+++ b/tests/context.py
@@ -0,0 +1,3 @@
+from utils.fix_string import string_test, string_to_float
+from utils.mann_kendall import mk_test
+
diff --git a/tests/test_fix_string.py b/tests/test_fix_string.py
new file mode 100644
index 0000000..189e724
--- /dev/null
+++ b/tests/test_fix_string.py
@@ -0,0 +1,19 @@
+import pytest
+
+from .context import string_test, string_to_float
+
+
+def test_string_to_float():
+    value = "< 2"
+    string = 'test<'
+    assert 2 == string_to_float(value)
+    assert type(string_to_float(value)) == float
+    with pytest.raises(ValueError):
+        string_to_float(string)
+
+
+def test_string_to_test():
+    value = "2"
+    string = 'test'
+    assert None == string_test(value)
+    assert 'test' == string_test(string)