some fine-tuning: clarify documentation, add variables for easier debugging

diff --git a/testing/volume_size_accuracy.py b/testing/volume_size_accuracy.py
index fb32748..820499b 100755 (executable)
--- a/testing/volume_size_accuracy.py
+++ b/testing/volume_size_accuracy.py
@@ -11,14 +11,10 @@ By doing the following:
 - add a file that nearly fills the volume
 - add a small file that should just fit in or not
 - check expected number and size of volumes
-- repeat with max_volume_size +1, -1, +2, -2, +10, -10
-
-Repeat with compressed/encrypted data; for this have to find some random data
-that is repeatable (--> :py:mod:`create_pseudo_random_files`) and experiment a
-bit for suitable seeds and sizes
-
-e.g. for max_volume_size = RECORDSIZE + 1 * BLOCKSIZE
+- repeat with max_volume_size +1, +2, +10, ...
+- repeat with file sizes -1, -2, -10, ...
 
+e.g. for max_volume_size = RECORDSIZE + 1 * BLOCKSIZE:
 File 0 has Info0 and blocks Dat00, Dat01, ... Dat0K, (Dat0L, Dat0M, Dat0N)
 File 1 has Info1 and blocks Dat10, (Dat11)
                                                                 end of   end of
@@ -34,10 +30,12 @@ vol0: | Info0 | Dat00 | Dat01 | ... | Dat0K | Info1 | Dat10 |   0   |   0   |
       +-------+-------+-------+ ... +-------+-------+-------+-------+-------+
 
 2: file0 needs next block: blocks = [MAX_VOLUME_BLOCKS-4, 1]
+   --> will add one block of zeros after end of volume
 vol0: | Info0 | Dat00 | Dat01 | ... | Dat0K | Dat0L | Info1 | Dat10 |   0   | 0
       +-------+-------+-------+ ... +-------+-------+-------+-------+-------+
 
 3: file0 needs 2 more blocks: blocks = [MAX_VOLUME_BLOCKS-3, 1]
+   --> will add two blocks of zeros after end of volume
 vol0: | Info0 | Dat00 | Dat01 | ... | Dat0K | Dat0L | Dat0M | Info1 | Dat10 |00
       +-------+-------+-------+ ... +-------+-------+-------+-------+-------+
 
@@ -53,12 +51,12 @@ vol1: |  VOL  | Dat11 |   0   |   0   |     |       |       |       |       |
 
 6: both need next block: blocks = [MAX_VOLUME_BLOCKS-4, 2]
 vol0: | Info0 | Dat00 | Dat01 | ... | Dat0K | Dat0L | Info1 | Dat10 |       |
-vol1: |  VOL  | Dat11 |   0   |   0   |     |       |       |       |       |
+vol1: |  VOL  | Dat11 |   0   |0|...|       |       |       |       |       |
       +-------+-------+-------+ ... +-------+-------+-------+-------+-------+
 
-single huge file: blocks = [MAX_VOLUME_BLOCKS * 3,]
+(not tested: single huge file)
 vol0: | Info0 | Dat00 | Dat01 | ... | Dat02 | Dat03 | Dat04 |  wasted space |
-vol1: |  VOL  | Dat05 | Dat06 | Dat07 | ... | Dat08 | Dat09 |  wasted space |
+vol1: |  VOL  | Dat05 | Dat06 | ... | Dat07 | Dat08 | Dat09 |  wasted space |
 vol2: |  ...  |       |       |     |       |       |       |       |       |
       +-------+-------+-------+ ... +-------+-------+-------+-------+-------+
 
@@ -89,6 +87,9 @@ N_BLOCKS_PER_RECORD = RECORDSIZE // BLOCKSIZE
 #: number of blocks per tar volume file
 MAX_VOLUME_BLOCKS = N_BLOCKS_PER_RECORD + 1
 
+#: always print all test output; will produce ~10 lines of text for each of the
+#: ~48000 tests --> not recommended
+ALWAYS_PRINT_EVERYTHING = False
 
 def fill_file(file_handle, data_size):
     """ fill given file handle with nonsense data of given size """
@@ -117,11 +118,12 @@ def test(temp_dir, file_blocks, volume_blocks_arg, offset_blocks,
          file_size_offsets=(0, 0), volume_size_offset=0):
     """ create TarFile with given configuration """
 
-    # use "delayed" print dprnt, that only prints if necessary (i.e. something
-    # went wrong)
+    # use delayed + conditional print dprnt, that only prints if necessary
+    # (i.e. if something went wrong)
     output = []
     dprnt = output.append
 
+    dprnt('-' * 72)
     dprnt('testing with {} file blocks, expect {} volume blocks'
           .format(file_blocks, volume_blocks_arg))
     dprnt('expect offsets to be {} blocks'.format(offset_blocks))
@@ -238,7 +240,7 @@ def test(temp_dir, file_blocks, volume_blocks_arg, offset_blocks,
                           size_str(expected_blocks * BLOCKSIZE)))
 
     # print output only if something went wrong
-    if not everything_ok:
+    if (not everything_ok) or ALWAYS_PRINT_EVERYTHING:
         for line in output:
             print(line)
 
@@ -272,12 +274,12 @@ def main():
     n_errs = 0
     n_tests = 0
     n_tests_overall = len(tests) * len(size_offsets)**3
-    with TemporaryDirectory() as temp_dir:
+    with TemporaryDirectory(prefix='deltatar_test_') as temp_dir:
         for size_comb_idx, (file_sizes, vol_sizes, offsets) \
                 in enumerate(tests):
             if fast_fail and n_errs > 0:
                 break
-            print('-' * 72)
+            print('=' * 72)
             print('size combination {}: ({}, {})'
                   .format(size_comb_idx, *file_sizes))
             for volume_size_offset in size_offsets:
@@ -300,6 +302,9 @@ def main():
                                  volume_size_offset=volume_size_offset)
                         if not test_succeeded:
                             n_errs += 1
+                            if fast_fail:
+                                print('stopping after test {} (fast-fail set)'
+                                      .format(n_tests))
 
     return n_errs