Enhanced Branch Coverage

[hunterjm]

Expected Result

When running code coverage on a project, all branches in a method will be determined, and their targets will be instrumented.

Actual Result

Currently, only sequence points that are targets of branches are instrumented.

Proposed Solution

Implement a branch point/target search using logic similar to OpenCover.Framework.Symbols.CecilSymbolManager. This would allow us to:

• Track Branches separately from Sequence Points.
• Instrument all Branch Targets.
• Provide more detailed branch information to the supported reporters.

Discussion

I've already taken an initial stab at this functionality in my fork and everything seems to be working. I am in the process of cleaning up the code and adding tests, but wanted to open this issue before opening a PR.

Major high-level changes to the structure are as follows:

• Removed IsBranchTarget from Line and LineInfo as branches are now tracked separately from sequence points.
• Changed InstrumenterResult
  • Added Branch which extends Line and adds additional properties such as Path
  • Changed Document to have both Lines and Branches
• Changed CoverageResult
  • Updated Methods to be a Dictionary with a new class Method as the Value
  • Method contains Lines and Branches
• Changed all supporting code (Instrumenter, CoverageSummary, Reporters) to handle the new model structure.

[tonerdo]

@hunterjm Thanks for opening this issue and taking a stab at fixing it. I look forward to your PR. Cheers

[tonerdo]

New release here: https://www.nuget.org/packages/coverlet.msbuild/2.0.0