Fixes #21: merge test coverage with e2e tests in CI

[Reactivity512]

Fixes #21: merge test coverage with e2e tests in CI

[metafates]

Thank you! Left some review comments

[metafates]

Let's inline this so that workflow won't depend on Makefile

[metafates]

.PHONY isn't needed here because we have MAKEFLAGS += --always-make

[metafates]

If possible, I think we should avoid relying on third-party tools.

I think we can simplify this a bit.

Overall, it should look like this:

1. go test ./... - run unit tests
2. go test -tags e2e -count 1 ./examples_test.go - run e2e tests
3. go test -tags example -coverprofile coverage.out -coverpkg ./... ./... || true - run both unit tests and examples (which are invoked from e2e).

[Reactivity512]

I suggest two options:

1. Simple, but it requires running unit tests twice (first without coverage, then again during the general test run)

# Run unit tests separately to catch errors
go test -race -v ./...

# Run all tests together for coverage (ignoring failures)
go test -race -v -tags e2e -coverprofile=coverage.out -coverpkg=./... ./... || true

go tool cover -func=coverage.out
go tool cover -html=coverage.out -o coverage/coverage.html

2. Using go tool covdata. This is the official Go tool introduced in v1.20, designed exactly for this use case.

mkdir -p coverage/unit coverage/e2e coverage/merged

# Run unit tests and save raw coverage data to coverage/unit
go test -race -v -coverpkg=./... ./... -test.gocoverdir=coverage/unit

# Run e2e tests and save raw coverage data to coverage/e2e (ignoring failures)
go test -race -v -tags e2e -coverpkg=./... ./... -test.gocoverdir=coverage/e2e || true

# Merge data from both directories into coverage/merged
go tool covdata merge -i=coverage/unit,coverage/e2e -o=coverage/merged

# Convert merged data to text format (coverage.out)
go tool covdata textfmt -i=coverage/merged -o=coverage.out

# Generate a report to the console
go tool cover -func=coverage.out

# Save the report to text and HTML files
go tool cover -func=coverage.out -o coverage/coverage.out
go tool cover -html=coverage.out -o coverage/coverage.html

Which approach do you think is more suitable?

[metafates]

Simple, but it requires running unit tests twice

I think it's good enough. Let's stick to this one.

But important note, though - running e2e won't affect the coverage, as it runs examples through separate process. We need to run those examples directly with example tag from examples/ dir with coverage.

[Reactivity512]

Great, then we can run it like this:

go test -race -v -tags e2e,example -coverprofile=coverage.out -coverpkg=./... ./... || true