add ctest integration tests for musrfit maxLH/chisq validation

Add a Python-based test script that runs musrfit -c on each example
msr-file, extracts the maxLH or chisq value, and checks it against
a reference value with a relative tolerance of 1e-4. Covers all 13
example msr-files (single histogram and asymmetry fits).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CMakeLists.txt

@@ -279,6 +279,10 @@ set(CMAKE_INSTALL_RPATH "${rpath}")
 #--- propagate to the sub-directories -----------------------------------------
 add_subdirectory(src)
 
+#--- testing ------------------------------------------------------------------
+enable_testing()
+add_subdirectory(tests)
+
 #--- write summary of the installation
 cmake_host_system_information(RESULT PROCESSOR QUERY PROCESSOR_DESCRIPTION)
 

tests/CMakeLists.txt

@@ -0,0 +1,2 @@
+#--- musrfit integration tests ------------------------------------------------
+add_subdirectory(maxLH_check)

tests/maxLH_check/CMakeLists.txt

@@ -0,0 +1,36 @@
+#--- maxLH_check test (Python) ------------------------------------------------
+
+find_package(Python3 REQUIRED COMPONENTS Interpreter)
+
+#--- helper macro -------------------------------------------------------------
+macro(add_maxLH_test test_name msr_file expected_value)
+  add_test(
+    NAME ${test_name}
+    COMMAND Python3::Interpreter
+      ${CMAKE_CURRENT_SOURCE_DIR}/maxLH_check.py
+      $<TARGET_FILE:musrfit>
+      ${CMAKE_SOURCE_DIR}/doc/examples/${msr_file}
+      ${expected_value}
+      1e-4
+    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/doc/examples
+  )
+endmacro()
+
+#--- register ctest(s) -------------------------------------------------------
+
+# single histogram fits (maxLH)
+add_maxLH_test(test-histo-MusrRoot      test-histo-MusrRoot.msr       3971.7)
+add_maxLH_test(test-histo-PSI-BIN       test-histo-PSI-BIN.msr        663.89)
+add_maxLH_test(test-histo-ROOT-NPP      test-histo-ROOT-NPP.msr      249.12)
+add_maxLH_test(test-histo-HAL9500       test-histo-HAL9500.msr        1286509.8)
+add_maxLH_test(test-histo-HAL9500-RRF   test-histo-HAL9500-RRF.msr   22187.4)
+add_maxLH_test(test-histo-muMinus       test-histo-muMinus.msr        238962.6)
+add_maxLH_test(test-histo-NeXus         test-histo-NeXus.msr          3273.57)
+add_maxLH_test(test-histo-NeXus2        test-histo-NeXus2.msr         2582.50)
+
+# asymmetry fits (chisq)
+add_maxLH_test(test-asy-PSI-BIN         test-asy-PSI-BIN.msr          566.76)
+add_maxLH_test(test-asy-MUD             test-asy-MUD.msr              133.96)
+add_maxLH_test(test-asy-NeXus2          test-asy-NeXus2.msr           796.72)
+add_maxLH_test(test-asy-HAL9500-RRF     test-asy-HAL9500-RRF.msr     7402.28)
+add_maxLH_test(test-asy-LF-BaB6         test-asy-LF-BaB6.msr         1911.88)

tests/maxLH_check/maxLH_check.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+"""
+Runs musrfit -c on a given msr-file, extracts the maxLH (or chisq)
+value from stdout, and compares it against an expected reference value.
+Returns exit code 1 if the relative deviation exceeds the tolerance.
+
+Usage:
+  maxLH_check.py <musrfit> <msr-file> <expected_value> [tolerance]
+"""
+
+import subprocess
+import sys
+import re
+
+def main():
+    if len(sys.argv) < 4 or len(sys.argv) > 5:
+        print(f"usage: {sys.argv[0]} <musrfit> <msr-file> <expected> [tolerance]")
+        return 1
+
+    musrfit  = sys.argv[1]
+    msr_file = sys.argv[2]
+    expected = float(sys.argv[3])
+    tol      = float(sys.argv[4]) if len(sys.argv) == 5 else 1e-4
+
+    # run musrfit -c
+    result = subprocess.run([musrfit, "-c", msr_file],
+                            capture_output=True, text=True)
+    if result.returncode != 0:
+        print(f"**ERROR** musrfit returned exit code {result.returncode}")
+        print(result.stdout + result.stderr)
+        return 1
+
+    # extract maxLH or chisq from stdout
+    match = re.search(r">>\s+(maxLH|chisq)\s*=\s*([0-9.eE+-]+)", result.stdout)
+    if not match:
+        print("**ERROR** could not extract maxLH or chisq from output:")
+        print(result.stdout)
+        return 1
+
+    label = match.group(1)
+    value = float(match.group(2))
+    rel_dev = abs((value - expected) / expected)
+
+    if rel_dev > tol:
+        print(f"FAIL: {label} = {value}, expected = {expected}, "
+              f"rel. deviation = {rel_dev:.6e} > {tol:.6e}")
+        return 1
+
+    print(f"PASS: {label} = {value}, expected = {expected}, "
+          f"rel. deviation = {rel_dev:.6e} <= {tol:.6e}")
+    return 0
+
+if __name__ == "__main__":
+    sys.exit(main())