QoL improvements when running a subset of the expression tests

makefile

@@ -87,6 +87,7 @@ doxygen:
 clean:
 	@echo '  removing generated test files'
 	@$(RM) $(wildcard test/prob/generate_tests$(EXE))
+	@$(RM) $(EXPRESSION_TESTS) $(call findfiles,test/expressions,*_test.cpp)
 	@$(RM) $(call findfiles,test/prob,*_generated_v_test.cpp)
 	@$(RM) $(call findfiles,test/prob,*_generated_vv_test.cpp)
 	@$(RM) $(call findfiles,test/prob,*_generated_fd_test.cpp)

runTests.py

@@ -383,7 +383,7 @@ def checkToolchainPathWindows():
             universal_newlines=True,
         )
         out, err = p1.communicate()
-        if re.search(" |\(|\)", out):
+        if re.search(r" |\(|\)", out):
             stopErr(
                 "The RTools toolchain is installed in a path with spaces or bracket. Please reinstall to a valid path.",
                 -1,

test/generate_expression_tests.py

@@ -29,6 +29,9 @@ def save_tests_in_files(N_files, tests):
     for i in range(N_files):
         start = i * len(tests) // N_files
         end = (i + 1) * len(tests) // N_files
+        if start >= end:
+            # don't try to compile an empty file
+            continue
         with open(src_folder + "tests%d_test.cpp" % i, "w") as out:
             out.write("#include <test/expressions/expression_test_helpers.hpp>\n\n")
             for test in tests[start:end]:
@@ -125,5 +128,5 @@ def main(functions=(), j=1):
                     code = cg.cpp(),
                 )
             )
-    
+
     save_tests_in_files(j, tests)

test/sig_utils.py

@@ -132,7 +132,7 @@ def get_cpp_type(stan_type):
     "uniform_lcdf": [None, 0.2, 0.9],
     "uniform_lpdf": [None, 0.2, 0.9],
     "uniform_rng": [0.2, 1.9, None],
-    "wiener_lpdf": [0.8, None, 0.4, None, None],
+    "wiener_lpdf": [0.8, None, 0.4, None, None, None, None, None],
 }
 
 # list of functions we do not test. These are mainly functions implemented in compiler