[API] Comply with W3C Trace Context

[psx95]

Fixes #74

Changes

• Fixes the listed failures in w3c trace-context compliance test suite.
• Adds a CI check which runs the w3c trace context tests for SPEC_LEVEL=1.
  • Test suites run are TraceContextTest & AdvancedTest.

Details

The following lists shows all the failing tests. Checked box indicates that the changes in this PR have fixed the test.

Currently failing tests from TraceContextTest suite

• test_traceparent_header_name_valid_casing
• test_traceparent_included_tracestate_missing
• test_traceparent_ows_handling
• test_traceparent_version_0xcc
• test_tracestate_all_allowed_characters
• test_tracestate_duplicated_keys
• test_tracestate_empty_header
• test_tracestate_header_name_valid_casing
• test_tracestate_included_traceparent_included
• test_tracestate_key_length_limit
• test_tracestate_member_count_limit
• test_tracestate_multiple_headers_different_keys
• test_tracestate_ows_handling

Currently failing tests from AdvancedTest suite

• test_multiple_requests_with_valid_traceparent

NOTE: The tests above were part of test suites TraceContextTest & AdvancedTest. These test suites Trace Context Level 1 support.

Current Status

All tests now passing. Test suites ran - TraceContextTest & AdvancedTest.

Additional Tasks

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[netlify]

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[codecov]

Codecov Report

Attention: Patch coverage is 63.63636% with 4 lines in your changes missing coverage. Please review.

Project coverage is 87.83%. Comparing base (497eaf4) to head (894c042).
Report is 154 commits behind head on main.

Files with missing lines	Patch %	Lines
...entelemetry/trace/propagation/http_trace_context.h	62.50%	3 Missing ⚠️
api/include/opentelemetry/trace/trace_state.h	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3115      +/-   ##
==========================================
+ Coverage   87.12%   87.83%   +0.72%     
==========================================
  Files         200      195       -5     
  Lines        6109     6138      +29     
==========================================
+ Hits         5322     5391      +69     
+ Misses        787      747      -40     

Files with missing lines	Coverage Δ
api/include/opentelemetry/common/string_util.h	100.00% <100.00%> (ø)
api/include/opentelemetry/trace/trace_state.h	97.60% <0.00%> (ø)
...entelemetry/trace/propagation/http_trace_context.h	92.76% <62.50%> (-2.83%)	⬇️

... and 99 files with indirect coverage changes

[marcalff]

Nice work.

Please check the PR comments, it seems entry for test_traceparent_header_name_valid_casing is duplicated.

See also minor comments.

[marcalff]

LGTM, thanks for the fixes.

[lalitb]

LGTM with nit comments. Thanks for working on this.