tests: Add infrastructure to run Python unit tests

- Add UHD_ADD_PYTEST() CMake macro
- Add CMake code to tests/CMakeLists.txt to auto-run all registered
  Python unit tests
- Add a token unit test (it replicates parts of ranges_test.cpp)

The way Python-based unit tests are implemented in UHD is that they can
import uhd, and then operate on the module as usual.

Writing unit tests in Python instead of C++ can have multiple
advantages:
- If they test PyBind-wrapped C++ code, they can test both the binding
  and the underlying C++ code at once
- Writing unit tests in Python may be more concise

3 files changed, 49 insertions, 0 deletions

diff --git a/host/cmake/Modules/UHDUnitTest.cmake b/host/cmake/Modules/UHDUnitTest.cmake
index 9a71ca2aa..f1f52addc 100644
--- a/host/cmake/Modules/UHDUnitTest.cmake
+++ b/host/cmake/Modules/UHDUnitTest.cmake
@@ -104,3 +104,15 @@ function(UHD_ADD_TEST test_name)
     endif(WIN32)
 
 endfunction(UHD_ADD_TEST)
+
+########################################################################
+# Add a Python unit test
+########################################################################
+function(UHD_ADD_PYTEST test_name)
+    add_test(NAME ${test_name}
+        COMMAND ${RUNTIME_PYTHON_EXECUTABLE} -m unittest discover
+                                             -s ${CMAKE_CURRENT_SOURCE_DIR}
+                                             -p "${test_name}.*"
+        WORKING_DIRECTORY "${CMAKE_BINARY_DIR}/python"
+    )
+endfunction(UHD_ADD_PYTEST)
diff --git a/host/tests/CMakeLists.txt b/host/tests/CMakeLists.txt
index 6207987ef..bc0ff8b3b 100644
--- a/host/tests/CMakeLists.txt
+++ b/host/tests/CMakeLists.txt
@@ -64,6 +64,12 @@ set(test_sources
     multichan_register_iface_test.cpp
 )
 
+# Note: Python-based tests cannot have the same name as a C++-based test (i.e.,
+# only differ in the cpp/py file extension). If in doubt, prepend 'py'
+set(pytest_sources
+    pyranges_test.py
+)
+
 #turn each test cpp file into an executable with an int main() function
 add_definitions(-DBOOST_TEST_DYN_LINK -DBOOST_TEST_MAIN)
 
@@ -98,6 +104,17 @@ foreach(benchmark_source ${benchmark_sources})
     UHD_INSTALL(TARGETS ${benchmark_name} RUNTIME DESTINATION ${PKG_LIB_DIR}/tests COMPONENT tests)
 endforeach(benchmark_source)
 
+if(ENABLE_PYTHON_API)
+    foreach(test_source ${pytest_sources})
+        get_filename_component(test_name ${test_source} NAME_WE)
+        UHD_ADD_PYTEST(${test_name})
+    endforeach(test_source)
+    UHD_INSTALL(FILES ${pytest_sources}
+        DESTINATION ${PKG_LIB_DIR}/tests
+        COMPONENT tests
+    )
+endif(ENABLE_PYTHON_API)
+
 ###############################################################################
 # Add a unit test that requires linkage to internal parts of UHD which are not
 # API
diff --git a/host/tests/pyranges_test.py b/host/tests/pyranges_test.py
new file mode 100644
index 000000000..17137e9f2
--- /dev/null
+++ b/host/tests/pyranges_test.py
@@ -0,0 +1,20 @@
+#
+# Copyright 2020 Ettus Research, a National Instruments Brand
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+"""
+Unit test for uhd.types.*Range
+"""
+
+import unittest
+import uhd
+
+class RangesTest(unittest.TestCase):
+    """ Test Python-wrapped ranges classes """
+    def test_meta_range(self):
+        """ Test MetaRange.clip() """
+        my_range = uhd.types.MetaRange(1.0, 10.0, 0.5)
+        self.assertEqual(my_range.clip(5.0), 5.0)
+        self.assertEqual(my_range.clip(11.0), 10.0)
+        self.assertEqual(my_range.clip(5.1, True), 5.0)