Add read tests to ensure backwards compatibility (key4hep#358)

* Add backwards compatibility tests using downloaded files

* Add basic version checks to reading files

* Run pytest with more output

* Update test files to the tagged versions

* Avoid polluting the test output to make them fail

The gaudi_fixtures that have been introduced with v39 include the full
python file otherwise, which matches the FAIL_REGULAR_EXPRESSION and
makes the test fail even though they are actually passing

CMakeLists.txt

@@ -67,9 +67,9 @@ find_package(nlohmann_json 3.10.5)
 
 add_subdirectory(edm4hep)
 add_subdirectory(utils)
-add_subdirectory(test)
 add_subdirectory(tools)
 add_subdirectory(python)
+add_subdirectory(test)
 
 #--- create uninstall target ---------------------------------------------------
 include(cmake/EDM4HEPUninstall.cmake)

test/CMakeLists.txt

@@ -44,7 +44,6 @@ set_tests_properties(
 
   PROPERTIES
    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-   FAIL_REGULAR_EXPRESSION ""
 )
 
 add_executable(write_events write_events.cc)
@@ -127,3 +126,13 @@ set_property(TEST py_test_module APPEND PROPERTY ENVIRONMENT
 
 add_subdirectory(utils)
 add_subdirectory(tools)
+
+
+include(ExternalData)
+list(APPEND ExternalData_URL_TEMPLATES
+  "https://key4hep.web.cern.ch:443/testFiles/EDM4hep/%(hash)"
+)
+
+add_subdirectory(backwards_compat)
+
+ExternalData_Add_Target(backward_compat_tests)

test/backwards_compat/CMakeLists.txt

@@ -0,0 +1,15 @@
+ExternalData_Add_Test(backward_compat_tests
+  NAME backwards_compat_v00-99 COMMAND pytest -v --inputfile=DATA{${CMAKE_CURRENT_SOURCE_DIR}/input_files/edm4hep_example_v00-99-01_podio_v01-01.root})
+set_test_env(backwards_compat_v00-99)
+
+ExternalData_Add_Test(backward_compat_tests
+  NAME backwards_compat_rntuple_v00-99 COMMAND pytest -v --inputfile=DATA{${CMAKE_CURRENT_SOURCE_DIR}/input_files/edm4hep_example_rntuple_v00-99-01_podio_v01-01.root})
+set_test_env(backwards_compat_rntuple_v00-99)
+
+set_tests_properties(
+  backwards_compat_v00-99
+  backwards_compat_rntuple_v00-99
+
+  PROPERTIES
+    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}/test
+)

test/backwards_compat/input_files/edm4hep_example_rntuple_v00-99-01_podio_v01-01.root.md5

@@ -0,0 +1 @@
+a725377f2bb515f7d91b953b7a1fc964

test/backwards_compat/input_files/edm4hep_example_v00-99-01_podio_v01-01.root.md5

@@ -0,0 +1 @@
+bd4006fb7a56fa765ede88c2920eb351

test/pytest.ini

@@ -1,2 +1,2 @@
 [pytest]
-addopts = --ignore=test_rdf.py --ignore=tools --ignore=utils
+addopts = --ignore=test_rdf.py --ignore=tools --ignore=utils -p no:gaudi_fixtures

test/test_EDM4hepFile.py

@@ -4,11 +4,14 @@
 """
 
 import os
+import re
 import podio
 import edm4hep
 import pytest
 from itertools import count
 
+from edm4hep import __version__
+
 from conftest import options
 
 # For now simply copy these from createEDM4hepFile.py
@@ -30,6 +33,29 @@ def inputfile_name(pytestconfig):
     return pytestconfig.getoption("inputfile")
 
 
+VERSIONED_FILE_RGX = re.compile(
+    r"edm4hep_example_(?:rntuple_)?v(\d+-\d+(?:-\d+)?)_podio_v(\d+-\d+(?:-\d+)?).root"
+)
+
+
+@pytest.fixture(scope="module")
+def expected_edm4hep_version(inputfile_name):
+    """Get the expected edm4hep version from the file name"""
+    rgx_match = re.match(VERSIONED_FILE_RGX, inputfile_name)
+    if not rgx_match:
+        return podio.version.parse(__version__)
+    return podio.version.parse(rgx_match.group(1).replace("-", "."))
+
+
+@pytest.fixture(scope="module")
+def expected_podio_version(inputfile_name):
+    """Get the expected edm4hep version from the file name"""
+    rgx_match = re.match(VERSIONED_FILE_RGX, inputfile_name)
+    if not rgx_match:
+        return podio.version.build_version
+    return podio.version.parse(rgx_match.group(2).replace("-", "."))
+
+
 @pytest.fixture(scope="module")
 def reader(inputfile_name):
     """Get the reader for the passed filename"""
@@ -77,9 +103,13 @@ def check_cov_matrix(cov_matrix, n_dim):
         assert cov_matrix[i] == next(counter)
 
 
-def test_basic_file_contents(events):
+def test_basic_file_contents(
+    reader, events, expected_edm4hep_version, expected_podio_version
+):
     """Make sure the basic file contents are OK"""
     assert len(events) == FRAMES
+    assert reader.current_file_version("edm4hep") == expected_edm4hep_version
+    assert reader.current_file_version() == expected_podio_version
 
 
 def test_EventHeaderCollection(event):