1""" 2Utilities for truncating assertion output. 3 4Current default behaviour is to truncate assertion explanations at 5~8 terminal lines, unless running in "-vv" mode or running on CI. 6""" 7from __future__ import absolute_import, division, print_function 8import os 9 10import six 11 12 13DEFAULT_MAX_LINES = 8 14DEFAULT_MAX_CHARS = 8 * 80 15USAGE_MSG = "use '-vv' to show" 16 17 18def truncate_if_required(explanation, item, max_length=None): 19 """ 20 Truncate this assertion explanation if the given test item is eligible. 21 """ 22 if _should_truncate_item(item): 23 return _truncate_explanation(explanation) 24 return explanation 25 26 27def _should_truncate_item(item): 28 """ 29 Whether or not this test item is eligible for truncation. 30 """ 31 verbose = item.config.option.verbose 32 return verbose < 2 and not _running_on_ci() 33 34 35def _running_on_ci(): 36 """Check if we're currently running on a CI system.""" 37 env_vars = ['CI', 'BUILD_NUMBER'] 38 return any(var in os.environ for var in env_vars) 39 40 41def _truncate_explanation(input_lines, max_lines=None, max_chars=None): 42 """ 43 Truncate given list of strings that makes up the assertion explanation. 44 45 Truncates to either 8 lines, or 640 characters - whichever the input reaches 46 first. The remaining lines will be replaced by a usage message. 47 """ 48 49 if max_lines is None: 50 max_lines = DEFAULT_MAX_LINES 51 if max_chars is None: 52 max_chars = DEFAULT_MAX_CHARS 53 54 # Check if truncation required 55 input_char_count = len("".join(input_lines)) 56 if len(input_lines) <= max_lines and input_char_count <= max_chars: 57 return input_lines 58 59 # Truncate first to max_lines, and then truncate to max_chars if max_chars 60 # is exceeded. 61 truncated_explanation = input_lines[:max_lines] 62 truncated_explanation = _truncate_by_char_count(truncated_explanation, max_chars) 63 64 # Add ellipsis to final line 65 truncated_explanation[-1] = truncated_explanation[-1] + "..." 66 67 # Append useful message to explanation 68 truncated_line_count = len(input_lines) - len(truncated_explanation) 69 truncated_line_count += 1 # Account for the part-truncated final line 70 msg = '...Full output truncated' 71 if truncated_line_count == 1: 72 msg += ' ({0} line hidden)'.format(truncated_line_count) 73 else: 74 msg += ' ({0} lines hidden)'.format(truncated_line_count) 75 msg += ", {0}" .format(USAGE_MSG) 76 truncated_explanation.extend([ 77 six.text_type(""), 78 six.text_type(msg), 79 ]) 80 return truncated_explanation 81 82 83def _truncate_by_char_count(input_lines, max_chars): 84 # Check if truncation required 85 if len("".join(input_lines)) <= max_chars: 86 return input_lines 87 88 # Find point at which input length exceeds total allowed length 89 iterated_char_count = 0 90 for iterated_index, input_line in enumerate(input_lines): 91 if iterated_char_count + len(input_line) > max_chars: 92 break 93 iterated_char_count += len(input_line) 94 95 # Create truncated explanation with modified final line 96 truncated_result = input_lines[:iterated_index] 97 final_line = input_lines[iterated_index] 98 if final_line: 99 final_line_truncate_point = max_chars - iterated_char_count 100 final_line = final_line[:final_line_truncate_point] 101 truncated_result.append(final_line) 102 return truncated_result 103