refactor: changing evaluation lib etc (#45)

## Description

<!-- Provide a brief description of your changes -->

## Related Issue

<!-- Link to the related issue(s) -->
Closes #

## Type of Change

<!-- Mark the relevant option with an "x" -->

- [ ] `feat`: New feature (minor version bump)
- [ ] `fix`: Bug fix (patch version bump)
- [ ] `docs`: Documentation only changes
- [ ] `chore`: Maintenance tasks, dependency updates
- [ ] `refactor`: Code refactoring without functional changes
- [ ] `test`: Adding or updating tests
- [ ] `ci`: CI/CD changes
- [ ] `perf`: Performance improvements
- [ ] `build`: Build system changes
- [ ] `style`: Code style/formatting changes

## PR Title Format

**IMPORTANT**: Since we use squash and merge, your PR title will become
the commit message. Please ensure your PR title follows the
[Conventional Commits](https://www.conventionalcommits.org/) format:

```
<type>(<optional-scope>): <description>
```

### Examples:
- `feat(operators): add new string comparison operator`
- `fix(wasm): correct memory allocation bug`
- `docs: update API examples in README`
- `chore(deps): update rust dependencies`

For breaking changes, use `!` after the type/scope or include `BREAKING
CHANGE:` in the PR description:
- `feat(api)!: redesign evaluation API`

## Testing

<!-- Describe the testing you've performed -->

- [ ] Unit tests added/updated
- [ ] Integration tests added/updated
- [ ] Manual testing performed
- [ ] All tests pass (`cargo test`)
- [ ] Code is formatted (`cargo fmt`)
- [ ] Clippy checks pass (`cargo clippy -- -D warnings`)
- [ ] WASM builds successfully (if applicable)

## Breaking Changes

<!-- If this introduces breaking changes, describe them here -->

- [ ] This PR includes breaking changes
- [ ] Documentation has been updated to reflect breaking changes
- [ ] Migration guide included (if needed)

## Additional Notes

<!-- Any additional information, context, or screenshots -->

---------

Signed-off-by: Simon Schrottner <simon.schrottner@dynatrace.com>
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: aepfli

.cargo/config.toml

@@ -0,0 +1,7 @@
+# Cargo configuration for flagd-evaluator
+
+# Disable SIMD for WASM target (Chicory doesn't support V128/SIMD128)
+[target.wasm32-unknown-unknown]
+rustflags = [
+    "-C", "target-feature=-simd128"
+]

.github/workflows/ci.yml

@@ -76,64 +76,6 @@ jobs:
       - name: Check formatting
         run: cargo fmt -- --check
 
-  build-cli:
-    name: Build CLI
-    strategy:
-      matrix:
-        include:
-          - os: ubuntu-latest
-            target: x86_64-unknown-linux-gnu
-            artifact: flagd-eval
-          - os: macos-latest
-            target: x86_64-apple-darwin
-            artifact: flagd-eval
-          - os: windows-latest
-            target: x86_64-pc-windows-msvc
-            artifact: flagd-eval.exe
-    runs-on: ${{ matrix.os }}
-    steps:
-      - uses: actions/checkout@v4
-
-      - name: Install Rust
-        uses: dtolnay/rust-toolchain@stable
-        with:
-          targets: ${{ matrix.target }}
-
-      - name: Cache cargo
-        uses: actions/cache@v4
-        with:
-          path: |
-            ~/.cargo/bin/
-            ~/.cargo/registry/index/
-            ~/.cargo/registry/cache/
-            ~/.cargo/git/db/
-            target/
-          key: ${{ runner.os }}-cargo-cli-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-cargo-cli-
-
-      - name: Build CLI
-        run: cargo build --release --bin flagd-eval
-
-      - name: Test CLI binary
-        run: |
-          ./target/release/${{ matrix.artifact }} --help
-          ./target/release/${{ matrix.artifact }} operators
-        shell: bash
-
-      - name: Validate example files
-        run: |
-          ./target/release/${{ matrix.artifact }} eval --rule @examples/rules/basic.json --data '{"age": 25}'
-          ./target/release/${{ matrix.artifact }} test examples/rules/test-suite.json
-        shell: bash
-
-      - name: Upload CLI artifact
-        uses: actions/upload-artifact@v4
-        with:
-          name: flagd-eval-${{ matrix.target }}
-          path: target/release/${{ matrix.artifact }}
-          retention-days: 30
-
   build-wasm:
     name: Build WASM
     runs-on: ubuntu-latest

.github/workflows/release.yml

@@ -30,80 +30,6 @@ jobs:
           config-file: release-please-config.json
           manifest-file: .release-please-manifest.json
 
-  build-cli:
-    name: Build CLI (${{ matrix.target }})
-    needs: release-please
-    if: always() && (needs.release-please.outputs.release_created == 'true' || startsWith(github.ref, 'refs/tags/'))
-    strategy:
-      matrix:
-        include:
-          - os: ubuntu-latest
-            target: x86_64-unknown-linux-gnu
-            artifact: flagd-eval
-            archive: flagd-eval-linux-x64.tar.gz
-          - os: macos-latest
-            target: x86_64-apple-darwin
-            artifact: flagd-eval
-            archive: flagd-eval-macos-x64.tar.gz
-          - os: macos-latest
-            target: aarch64-apple-darwin
-            artifact: flagd-eval
-            archive: flagd-eval-macos-arm64.tar.gz
-          - os: windows-latest
-            target: x86_64-pc-windows-msvc
-            artifact: flagd-eval.exe
-            archive: flagd-eval-windows-x64.zip
-    runs-on: ${{ matrix.os }}
-    steps:
-      - uses: actions/checkout@v4
-
-      - name: Install Rust
-        uses: dtolnay/rust-toolchain@stable
-        with:
-          targets: ${{ matrix.target }}
-
-      - name: Cache cargo
-        uses: actions/cache@v4
-        with:
-          path: |
-            ~/.cargo/bin/
-            ~/.cargo/registry/index/
-            ~/.cargo/registry/cache/
-            ~/.cargo/git/db/
-            target/
-          key: ${{ runner.os }}-${{ matrix.target }}-cargo-release-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-${{ matrix.target }}-cargo-release-
-
-      - name: Build CLI
-        run: cargo build --release --target ${{ matrix.target }} --bin flagd-eval
-
-      - name: Create archive (Unix)
-        if: runner.os != 'Windows'
-        run: |
-          cd target/${{ matrix.target }}/release
-          tar czvf ../../../${{ matrix.archive }} ${{ matrix.artifact }}
-          cd ../../..
-          sha256sum ${{ matrix.archive }} > ${{ matrix.archive }}.sha256
-
-      - name: Create archive (Windows)
-        if: runner.os == 'Windows'
-        shell: pwsh
-        run: |
-          cd target/${{ matrix.target }}/release
-          Compress-Archive -Path ${{ matrix.artifact }} -DestinationPath ../../../${{ matrix.archive }}
-          cd ../../..
-          $hash = (Get-FileHash ${{ matrix.archive }} -Algorithm SHA256).Hash.ToLower()
-          "$hash  ${{ matrix.archive }}" | Out-File -Encoding ASCII ${{ matrix.archive }}.sha256
-
-      - name: Upload CLI artifact
-        uses: actions/upload-artifact@v4
-        with:
-          name: cli-${{ matrix.target }}
-          path: |
-            ${{ matrix.archive }}
-            ${{ matrix.archive }}.sha256
-
   build-wasm:
     name: Build WASM
     needs: release-please
@@ -169,17 +95,10 @@ jobs:
 
   create-release:
     name: Create Release
-    needs: [release-please, build-cli, build-wasm]
+    needs: [release-please, build-wasm]
     if: always() && (needs.release-please.outputs.release_created == 'true' || startsWith(github.ref, 'refs/tags/'))
     runs-on: ubuntu-latest
     steps:
-      - name: Download CLI artifacts
-        uses: actions/download-artifact@v4
-        with:
-          pattern: cli-*
-          path: artifacts
-          merge-multiple: true
-
       - name: Download WASM artifact
         uses: actions/download-artifact@v4
         with:

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "testbed"]
+	path = testbed
+	url = git@github.com:open-feature/flagd-testbed.git

CLAUDE.md

@@ -22,8 +22,6 @@ cargo build --target wasm32-unknown-unknown --no-default-features --release --li
 # WASM output location
 # target/wasm32-unknown-unknown/release/flagd_evaluator.wasm
 
-# Build CLI tool
-cargo build --release --bin flagd-eval
 ```
 
 ### Testing
@@ -34,7 +32,7 @@ cargo test
 
 # Run specific test file
 cargo test --test integration_tests
-cargo test --test cli_tests
+cargo test --test gherkin_tests
 
 # Run specific test by name
 cargo test test_fractional_operator
@@ -56,22 +54,6 @@ cargo fmt -- --check
 cargo clippy -- -D warnings
 ```
 
-### CLI Tool Usage
-
-```bash
-# Evaluate a JSON Logic rule
-cargo run --bin flagd-eval -- eval --rule '{"==": [1, 1]}' --data '{}'
-
-# Load rule/data from file (use @ prefix)
-cargo run --bin flagd-eval -- eval --rule @examples/rules/basic.json --data '{"age": 25}'
-
-# Run test suite
-cargo run --bin flagd-eval -- test examples/rules/test-suite.json
-
-# List available operators
-cargo run --bin flagd-eval -- operators
-```
-
 ## Architecture
 
 ### Core Design Principles
@@ -96,9 +78,7 @@ src/
 │   ├── starts_with.rs  # String prefix matching
 │   └── ends_with.rs    # String suffix matching
 ├── model/              # Flag configuration data structures
-├── validation.rs       # JSON Schema validation against flagd schemas
-└── bin/
-    └── flagd-eval.rs   # CLI tool for testing rules without WASM
+└── validation.rs       # JSON Schema validation against flagd schemas
 ```
 
 ### Key Architectural Concepts
@@ -142,7 +122,7 @@ strip = true         # Strip symbols
 panic = "abort"      # Remove panic unwinding infrastructure
 ```
 
-**No Default Features for WASM**: Always build with `--no-default-features` to exclude CLI dependencies (clap, colored) from WASM binary.
+**No Default Features for WASM**: Always build with `--no-default-features` to exclude unnecessary dependencies from WASM binary.
 
 ### Memory Safety Rules
 
@@ -171,7 +151,7 @@ Resolution reasons: `STATIC`, `DEFAULT`, `TARGETING_MATCH`, `DISABLED`, `ERROR`,
 
 ### Testing Philosophy
 
-**Integration Tests** (tests/integration_tests.rs): 72 comprehensive tests covering:
+**Integration Tests** (tests/integration_tests.rs): Comprehensive tests covering:
 - Basic JSON Logic operations
 - All custom operators (fractional, sem_ver, starts_with, ends_with)
 - Memory management
@@ -180,7 +160,7 @@ Resolution reasons: `STATIC`, `DEFAULT`, `TARGETING_MATCH`, `DISABLED`, `ERROR`,
 - Type-specific evaluation functions
 - Context enrichment ($flagd properties)
 
-**CLI Tests** (tests/cli_tests.rs): End-to-end tests for the flagd-eval binary.
+**Gherkin Tests** (tests/gherkin_tests.rs): Specification compliance tests using the official flagd testbed.
 
 **When to Run Tests**:
 - ✅ After making code changes that affect behavior
@@ -197,7 +177,6 @@ Resolution reasons: `STATIC`, `DEFAULT`, `TARGETING_MATCH`, `DISABLED`, `ERROR`,
 3. Register in `src/operators/mod.rs` via `create_evaluator()`
 4. Add tests in both unit tests and `tests/integration_tests.rs`
 5. Document in README.md under "Custom Operators" section
-6. Consider adding to CLI's `operators` command output
 
 **Modifying Flag Evaluation Logic**:
 1. Primary logic is in `src/evaluation.rs`
@@ -287,14 +266,14 @@ This project uses [Release Please](https://github.com/googleapis/release-please)
 **Core Production**:
 - `datalogic-rs` (4.0) - JSON Logic implementation
 - `serde`, `serde_json` - JSON serialization (no_std compatible with alloc)
-- `jsonschema` (0.37) - Flag configuration validation
-
-**CLI Only** (excluded from WASM):
-- `clap` - Command-line argument parsing
-- `colored` - Terminal colors
+- `boon` (0.6) - JSON Schema validation
+- `murmurhash3` - Hash function for fractional operator
+- `ahash` - Hash table implementation (SIMD-disabled for Chicory compatibility)
+- `getrandom` - Random number generation for WASM
 
 **Dev**:
-- `assert_cmd`, `predicates` - CLI integration testing
+- `cucumber` - Gherkin/BDD testing
+- `tokio` - Async runtime for tests
 
 ## Cross-Language Integration
 

Cargo.toml

@@ -13,28 +13,27 @@ categories = ["wasm", "web-programming"]
 [lib]
 crate-type = ["cdylib", "rlib"]
 
-[[bin]]
-name = "flagd-eval"
-path = "src/bin/flagd-eval.rs"
-
 [dependencies]
 datalogic-rs = "4.0"
 serde = { version = "1.0", features = ["derive", "alloc"], default-features = false }
 serde_json = { version = "1.0", features = ["alloc"], default-features = false }
-jsonschema = { version = "0.37", default-features = false }
-
-# CLI-only dependencies (used by the binary, not the WASM lib)
-clap = { version = "4.5", features = ["derive", "cargo"], optional = true }
-colored = { version = "2.1", optional = true }
-
-[features]
-default = ["cli"]
-cli = ["clap", "colored"]
+boon = "0.6"
+murmurhash3 = "0.0.5"
+# Override ahash to avoid SIMD/AES-NI instructions that break Chicory WASM compatibility
+# ahash is pulled in by boon and uses AES-NI by default
+# We disable default features and use compile-time-rng to avoid runtime randomness
+ahash = { version = "0.8.12", default-features = false, features = ["compile-time-rng"] }
+# Enable wasm_js feature for getrandom in WASM builds (required for wasm32-unknown-unknown)
+getrandom = { version = "0.3", features = ["wasm_js"] }
 
 [dev-dependencies]
 wasm-bindgen-test = "0.3"
 assert_cmd = "2.0"
 predicates = "3.0"
+cucumber = "0.22.1"
+tokio = { version = "1.0", features = ["macros", "rt-multi-thread"] }
+async-trait = "0.1"
+glob = "0.3"
 
 [profile.release]
 opt-level = "z"