diff --git a/test_polyfun.py b/test_polyfun.py
index b13b32e..e7b7faa 100644
--- a/test_polyfun.py
+++ b/test_polyfun.py
@@ -98,9 +98,10 @@ def test_munge_sumstats(tmpdir, python3_exe):
     output_file = os.path.join(tmpdir, outfile)
     gold_file = os.path.join(gold_dir, outfile)
     
-    retval = os.system('%s %s --sumstats %s --out %s --n 327209 --min-info 0.6 --min-maf 0.001'%(python3_exe, script_exe, input_file, output_file))
+    cmd = '%s %s --sumstats %s --out %s --n 327209 --min-info 0.6 --min-maf 0.001'%(python3_exe, script_exe, input_file, output_file)
+    retval = os.system(cmd)
     if retval != 0:
-        raise ValueError('munge_sumstats command failed')
+        raise ValueError('munge_sumstats command failed when running the following command:\n%s'%(cmd))
     
     compare_dfs(tmpdir, gold_dir, outfile)
     
@@ -123,26 +124,29 @@ def test_polyfun(tmpdir, python3_exe):
     plink_prefix =  os.path.join(example_dir, 'reference.')
     
     #polyfun stage 2
-    retval = os.system('%s %s --compute-h2-L2 --output-prefix %s --sumstats %s --ref-ld-chr %s --w-ld-chr %s --nnls-exact'%
-             (python3_exe, script_exe, output_prefix, sumstats_file, ref_ld_prefix, w_ld_prefix))
+    cmd = '%s %s --compute-h2-L2 --output-prefix %s --sumstats %s --ref-ld-chr %s --w-ld-chr %s --nnls-exact' % \
+             (python3_exe, script_exe, output_prefix, sumstats_file, ref_ld_prefix, w_ld_prefix)
+    retval = os.system(cmd)
     if retval != 0:
-        raise ValueError('PolyFun command failed')
+        raise ValueError('PolyFun command failed when running the following command:\n%s'%(cmd))
     for outfile in ['testrun.22.bins.parquet', 'testrun.22.snpvar_ridge_constrained.gz', 'testrun.22.snpvar_ridge.gz', 'testrun.22.l2.M']:
         compare_dfs(tmpdir, gold_dir, outfile)
         
     #polyfun stage 3
-    retval = os.system('%s %s --compute-ldscores --output-prefix %s --bfile-chr %s --nnls-exact'%
-             (python3_exe, script_exe, output_prefix, plink_prefix))    
+    cmd = '%s %s --compute-ldscores --output-prefix %s --bfile-chr %s --nnls-exact'% \
+             (python3_exe, script_exe, output_prefix, plink_prefix)
+    retval = os.system(cmd)
     if retval != 0:
-        raise ValueError('PolyFun command failed')
+        raise ValueError('PolyFun command failed when running the following command:\n%s'%(cmd))
              
     compare_dfs(tmpdir, gold_dir, 'testrun.22.l2.ldscore.parquet')
         
     #polyfun stage 4
-    retval = os.system('%s %s --compute-h2-bins --output-prefix %s --sumstats %s --w-ld-chr %s --nnls-exact'%
-             (python3_exe, script_exe, output_prefix, sumstats_file, w_ld_prefix))
+    cmd = '%s %s --compute-h2-bins --output-prefix %s --sumstats %s --w-ld-chr %s --nnls-exact'% \
+             (python3_exe, script_exe, output_prefix, sumstats_file, w_ld_prefix)
+    retval = os.system(cmd)
     if retval != 0:
-        raise ValueError('PolyFun command failed')
+        raise ValueError('PolyFun command failed when running the following command:\n%s'%(cmd))
     compare_dfs(tmpdir, gold_dir, 'testrun.22.snpvar_constrained.gz')
     
     
@@ -164,29 +168,29 @@ def test_polyloc(tmpdir, python3_exe):
     posterior_file = os.path.join(example_dir, 'posterior_betas.gz')
     
     #polyloc stage 1
-    polyloc_cmd = ('%s %s --compute-partitions --output-prefix %s --posterior %s --bfile-chr %s --nnls-exact'%
+    polyloc_cmd = ('%s %s --compute-partitions --output-prefix %s --posterior %s --bfile-chr %s --nnls-exact'% \
                     (python3_exe, script_exe, output_prefix, posterior_file, plink_prefix))
     retval = os.system(polyloc_cmd)
     if retval != 0:
-        raise ValueError('PolyLoc command failed')
+        raise ValueError('PolyLoc command failed when running the following command:\n%s'%(polyloc_cmd))
     for outfile in ['polyloc_test.22.bins.parquet', 'polyloc_test.22.l2.M']:
         compare_dfs(tmpdir, gold_dir, outfile)
         
     
     #polyloc stage 2
-    polyloc_cmd = ('%s %s --compute-ldscores --output-prefix %s --bfile-chr %s --nnls-exact'%
+    polyloc_cmd = ('%s %s --compute-ldscores --output-prefix %s --bfile-chr %s --nnls-exact'% \
                     (python3_exe, script_exe, output_prefix, plink_prefix))
     retval = os.system(polyloc_cmd)
     if retval != 0:
-        raise ValueError('PolyLoc command failed')
+        raise ValueError('PolyLoc command failed when running the following command:\n%s'%(polyloc_cmd))
     compare_dfs(tmpdir, gold_dir, 'polyloc_test.22.l2.ldscore.parquet')
     
     #polyloc stage 3
-    polyloc_cmd = ('%s %s --compute-polyloc --output-prefix %s --w-ld-chr %s --sumstats %s --nnls-exact'%
+    polyloc_cmd = ('%s %s --compute-polyloc --output-prefix %s --w-ld-chr %s --sumstats %s --nnls-exact'% \
                     (python3_exe, script_exe, output_prefix, w_ld_prefix, sumstats_file))
     retval = os.system(polyloc_cmd)
     if retval != 0:
-        raise ValueError('PolyLoc command failed')
+        raise ValueError('PolyLoc command failed when running the following command:\n%s'%(polyloc_cmd))
     for outfile in ['polyloc_test.bin_h2', 'polyloc_test.Mp']:
         compare_dfs(tmpdir, gold_dir, outfile)
         
@@ -205,9 +209,10 @@ def test_extract_snpvar(tmpdir, python3_exe):
     output_file = os.path.join(tmpdir, outfile)
     gold_file = os.path.join(gold_dir, outfile)    
     
-    retval = os.system('%s %s --sumstats %s --out %s'%(python3_exe, script_exe, input_file, output_file))
+    cmd = '%s %s --sumstats %s --out %s'%(python3_exe, script_exe, input_file, output_file)
+    retval = os.system(cmd)
     if retval != 0:
-        raise ValueError('extract_snpvar command failed')
+        raise ValueError('extract_snpvar command failed when running the following command:\n%s'%(cmd))
     compare_dfs(tmpdir, gold_dir, outfile)
 
 
@@ -244,7 +249,7 @@ def test_finemapper_susie(tmpdir, python3_exe):
     #print(finemapper_cmd)
     retval = os.system(finemapper_cmd)
     if retval != 0:
-        raise ValueError('finemapper command failed')
+        raise ValueError('finemapper command failed when running the following command:\n%s'%(cmd))
     compare_dfs(tmpdir, gold_dir, outfile, sort_column='SNP')
 
 
@@ -282,7 +287,7 @@ def test_finemapper_finemap(tmpdir, python3_exe, finemap_exe):
     #print(finemapper_cmd)
     retval = os.system(finemapper_cmd)
     if retval != 0:
-        raise ValueError('finemapper command failed')
+        raise ValueError('finemapper command failed when running the following command:\n%s'%(cmd))
     compare_dfs(tmpdir, gold_dir, outfile, sort_column='SNP')