Add CI.

Add all the ci files. Clippy is disabled. Code coverage is generated but needs
maintainer's intervention to give upload access to codecov.

.github/workflows/build.yaml

@@ -0,0 +1,41 @@
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+
+name: build
+
+jobs:
+
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust:
+          - stable
+          - nightly 
+        features:
+          - default
+    steps:
+      - name: checkout
+        uses: actions/checkout@v3
+      - name: Generate cache key
+        run: echo "${{ matrix.rust }} ${{ matrix.features }}" | tee .cache_key
+      - name: cache
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('.cache_key') }}-${{ hashFiles('**/Cargo.toml','**/Cargo.lock') }}
+      - name: Set default toolchain
+        run: rustup default ${{ matrix.rust }}
+      - name: Set profile
+        run: rustup set profile minimal
+      - name: Update toolchain
+        run: rustup update
+      - name: Build
+        run: cargo build --features ${{ matrix.features }}

.github/workflows/lint.yaml

@@ -0,0 +1,31 @@
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+
+name: lint
+
+jobs:
+
+  fmt:
+    name: rust fmt
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Set default toolchain
+        run: rustup default nightly
+      - name: Set profile
+        run: rustup set profile minimal
+      - name: Add rustfmt
+        run: rustup component add rustfmt
+      - name: Add clippy
+        run: rustup component add clippy
+      - name: Update toolchain
+        run: rustup update
+      - name: Check fmt
+        run: cargo fmt --all -- --check
+      - name: Clippy
+        #TODO: enable clippy when all clippy warnings are fixed.
+        #run: cargo clippy --all-targets --all-features -- -D warnings

.github/workflows/test.yaml

@@ -0,0 +1,42 @@
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+
+name: test
+
+jobs:
+  test_with_codecov:
+    name: Run tests with coverage reporting
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Set default toolchain
+        run: rustup default nightly
+      - name: Set profile
+        run: rustup set profile minimal
+
+      # Pin grcov to v0.8.2 because of build failure at 0.8.3
+      - name: Install grcov
+        run: cargo install grcov --force --version 0.8.2
+
+      # Tests are run with code coverage support
+      - name: Run cargo test
+        env:
+          CARGO_INCREMENTAL: '0'
+          RUSTFLAGS: '-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off'
+          RUSTDOCFLAGS: '-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off'
+        run: cargo test -- --nocapture
+      - id: coverage
+        name: Generate coverage
+        uses: actions-rs/[email protected]
+
+      # Upload coverage report
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v1
+        with:
+          file: ${{ steps.coverage.outputs.report }}
+          directory: ./coverage/reports/