diff --git a/tests/test_allcall.py b/tests/test_allcall.py
new file mode 100644
index 0000000..e727d4b
--- /dev/null
+++ b/tests/test_allcall.py
@@ -0,0 +1,13 @@
+from pyModeS import allcall
+
+
+def test_icao():
+    assert allcall.icao("5D484FDEA248F5") == "484FDE"
+
+
+def test_interrogator():
+    assert allcall.interrogator("5D484FDEA248F5") == 22
+
+
+def test_capability():
+    assert allcall.capability("5D484FDEA248F5")[0] == 5
diff --git a/tests/test_surv.py b/tests/test_surv.py
new file mode 100644
index 0000000..0286e27
--- /dev/null
+++ b/tests/test_surv.py
@@ -0,0 +1,22 @@
+from pyModeS import surv
+
+
+def test_fs():
+    assert surv.fs("2A00516D492B80")[0] == 2
+
+
+def test_dr():
+    assert surv.dr("2A00516D492B80")[0] == 0
+
+
+def test_um():
+    assert surv.um("200CBE4ED80137")[0] == 9
+    assert surv.um("200CBE4ED80137")[1] == 1
+
+
+def test_identity():
+    assert surv.identity("2A00516D492B80") == "0356"
+
+
+def test_altitude():
+    assert surv.altitude("20001718029FCD") == 36000