Fixing the float resolver

[arvkonstantin]

Adding optional plus and minus operators after scientific notation in the float resolver.

In some programming languages, scientific notation is represented without the "+" operator.
For example , in the Scala programming language , floating-point numbers and scientific notation look like this:

println(14266020.870271318)
1.4266020870271318E7

And if the yaml file was generated via Scala, and then parsed by the PyYAML library, then this number is perceived as a string.

I made a minor correction that adds the optional operators after scientific notation.

[perlpunk]

As you can see here http://yaml.org/type/float.html , for the YAML 1.1 float type the sign is not optional, and PyYAML implements YAML 1.1.
There is a PR for supporting YAML 1.2, where the sign is optional.
Here you can see all type definitions in both versions: https://perlpunk.github.io/yaml-test-schema/schemas.html

[perlpunk]

The PR tests are failing locally for me:

.................................................................................................................................................................................................................................
.................................................................................................................................................................................................................................
.................................................................................................................................................................................................................................
..................................Compare: >>'+0.3e3'<< >>+0.3e3<<
Input: >>!!str +0.3e3<<                       
['str', '+0.3e3', '+0.3e3']               
Compare: >>'.3e3'<< >>.3e3<<               
Input: >>!!str .3e3<<                           
['str', '.3e3', '.3e3']                               
Compare: >>'0.3e3'<< >>0.3e3<<
Input: >>!!str 0.3e3<<                   
['str', '0.3e3', '0.3e3']                
Input: >>+0.3e3<<                             
['str', '+0.3e3', '+0.3e3']                   
Compare: >>300.0<< >>+0.3e3<<                                     
Input: >>+0.3e3<<                                     
['str', '+0.3e3', '+0.3e3']                     
Input: >>.3e3<<                            
['str', '.3e3', '.3e3']                               
Compare: >>300.0<< >>.3e3<<                  
Input: >>.3e3<<                                          
['str', '.3e3', '.3e3']                     
Input: >>0.3e3<<                          
['str', '0.3e3', '0.3e3']                 
Compare: >>300.0<< >>0.3e3<<              
Input: >>0.3e3<<                        
['str', '0.3e3', '0.3e3']                             
Failed 9 / 261 tests                         
F................................................................................................................................................................................................................................
.................................................................................................................................................................................................................................
............................................................................................................................
===========================================================================
test_implicit_resolver(tests/data/yaml11.schema, tests/data/yaml11.schema-skip): FAILURE
Traceback (most recent call last):             
  File "tests/lib/test_appliance.py", line 59, in execute
    function(verbose=verbose, *filenames)
  File "tests/lib/test_schema.py", line 141, in test_implicit_resolver
    assert(False)
AssertionError: see below
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
---------------------------------------------------------------------------
tests/data/yaml11.schema:
# https://github.com/perlpunk/yaml-test-schema/blob/master/data/schema-yaml11.yaml
---
'!!bool FALSE': ['bool', 'false()', 'false']
'!!bool False': ['bool', 'false()', 'false']
...
---------------------------------------------------------------------------
tests/data/yaml11.schema-skip:    
load: {                            
  'Y': 1, 'y': 1, 'N': 1, 'n': 1,
  '!!bool Y': 1, '!!bool N': 1, '!!bool n': 1, '!!bool y': 1,
  }                             
dump: {                           
  '!!str N': 1, '!!str Y': 1, '!!str n': 1, '!!str y': 1,
  }                            
===========================================================================
TESTS: 1283                      
FAILURES: 1                 
error: Tests failed                  

Not sure why github actions succeed.

@nitzmahone any idea? I'm having trouble again finding the part where the actual tests are run :)
https://github.com/yaml/pyyaml/actions/runs/1529387177

[perlpunk]

There are several places where I can find failing tests, but they do not result in a failing workflow step: https://github.com/yaml/pyyaml/runs/4393221891?check_suite_focus=true#step:6:726

[perlpunk]

I vote for closing, see my comments.
But it should be investigated why the test failures didn't show up as failures.

[nitzmahone]

sigh just looked- because the ancient homegrown test runner isn't returning a nonzero exit code on test failures... Yet another reason to standardize: #588