- t/Makefile now uses GOPATH_LINUX_BIN for binary verification
- t/t.go automatically sets GOPATH_LINUX_BIN based on runtime.GOOS
- Add modular dependency check scripts in t/scripts/

The test runner now seamlessly works on macOS without manual
environment variable setup.

Update all systest docker-compose.yml files to mount the dgraph
binary from GOPATH_LINUX_BIN instead of hardcoded GOPATH/bin path.

This enables Docker-based tests to find the correct Linux binary
on both Linux and macOS systems.

- Add TESTING.md as comprehensive testing guide (renamed from
  TESTING_GUIDE.md)
- Update CONTRIBUTING.md to link to TESTING.md with quick start examples
- Simplify t/README.md macOS section to reflect automated build system
- Add cross-references between documentation files

The macOS testing instructions are now much simpler since the build
system handles cross-compilation automatically.

Add note explaining that manual installation isn't required since
AUTO_INSTALL=true make check/test handles dependencies automatically.

- Add language specifier to code block (MD040)
- Rename duplicate "How to Run" headings (MD024)
- Remove trailing colons from anti-pattern headings (MD026)

Shorter, clearer name for the environment variable that specifies
where Linux binaries are stored for Docker tests.

Add design document for unified `make test` entry point that supports:
- Environment variables (TAGS, SUITE, PKG, TEST, FUZZ, FUZZTIME)
- Helper targets (test-unit, test-integration2, etc.)
- Auto-generated help from ## comments
- Auto-discovery of fuzz test packages

Add three-way routing to the test target based on environment variables:
- TAGS: bypass t/ runner, run go test directly with build tags
- FUZZ: auto-discover and run fuzz tests in packages
- SUITE (default): delegate to existing t/ runner

Precedence: TAGS > FUZZ > SUITE

The TAGS path is for integration2/upgrade tests that don't need the
t/ runner's Docker Compose orchestration. The FUZZ path discovers
packages containing Fuzz* functions and runs each with configurable
FUZZTIME (default 300s).

- Change help output to use conventional Make syntax (make test VAR=value)
- Add benchmark example showing PKG variable with test-benchmark
- Update TESTING.md with all 11 test shortcuts and new syntax
- Update CONTRIBUTING.md testing section with new examples
- Align all documentation with current make help output

- Extract SUITE values from t/t.go's allowed list
- Discover TAGS values by scanning test files for //go:build directives
- Display both in make help output for better discoverability

…-all

- Change i.e. examples to put vars after 'make test' (more intuitive)
- Add test-all target for SUITE=all (completes helper target coverage)
- Update TESTING.md to match new help output format
- All SUITE and TAGS values now have corresponding helper targets

- Rename duplicate "Examples" heading to "Go Test Examples" in TESTING.md
- Remove docs/plans/ files that had hard tabs and other lint issues

Add appropriate shellcheck disable comments to suppress false positives:
- SC2310: Functions in conditionals (intentional pattern)
- SC2312: Masked return values (intentional)
- SC2329: "Unused" functions (sourced by other scripts)
- SC1091: Can't follow source (file exists at runtime)

Add an explicit error when GOPATH is empty to prevent make install from
writing to system root paths like /bin and /linux_arm64. Remove
test-results-summary.md which was not meant to be checked in.