feat(ci): migrates circleci to github actions

.github/workflows/build_and_test.yml

@@ -0,0 +1,185 @@
+name: Build and Test
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    container:
+      image: openjdk:8-jdk
+    env:
+      _JAVA_OPTIONS: "-Xmx3G -Xms2G"
+    defaults:
+      run:
+        working-directory: .
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup System Tools
+        run: |
+          apt update -y
+          apt install -y gnupg2 curl
+      - name: Install Node.js
+        run: |
+          curl -fsSL https://deb.nodesource.com/setup_16.x | bash -
+          apt-get install -y nodejs
+      - name: Check Node.js version
+        run: node --version
+      - name: Verify files
+        run: |
+          curl -sSL https://secchannel.rsk.co/SUPPORT.asc | gpg2 --import -
+          gpg2 --verify SHA256SUMS.asc && sha256sum --check SHA256SUMS.asc
+
+      - name: List Files in gradle Directory
+        run: ls -al gradle && ls -al gradle/wrapper
+
+      - uses: actions/cache@v4
+        name: Cache Gradle
+        with:
+          path: |
+            .gradle/caches
+            gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+      - name: Build
+        run: |
+          ./configure.sh
+          ./gradlew --no-daemon dependencies
+          ./gradlew --no-daemon --stacktrace build -x test
+          ls -la ./gradle/wrapper/gradle-wrapper.jar
+
+  tests:
+    needs: build
+    runs-on: ubuntu-latest
+    container:
+      image: openjdk:8-jdk
+    defaults:
+      run:
+        working-directory: .
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup System Tools
+        run: |
+          apt update -y
+          apt install -y curl
+      - name: Install Node.js
+        run: |
+          curl -fsSL https://deb.nodesource.com/setup_16.x | bash -
+          apt-get install -y nodejs
+      - name: Check Node.js version
+        run: node --version
+
+      - uses: actions/cache@v4
+        name: Restore gradle cache
+        with:
+          path: |
+            .gradle/caches
+            gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+      - name: Check Working Directory
+        run: pwd
+      - name: List Files in Current Directory
+        run: ls -al
+      - name: List Files in gradle Directory
+        run: ls -al gradle && ls -al gradle/wrapper
+
+      - name: Get Gradle jar
+        run: |
+          ./configure.sh
+
+      - name: Unit tests
+        run: |
+          chmod +x ./gradlew
+          ./gradlew --no-daemon --stacktrace test
+      - name: Integration tests
+        run: |
+          chmod +x ./gradlew
+          ./gradlew --no-daemon --stacktrace test
+
+      - name: Save test results
+        run: |
+          mkdir -p ~/junit/
+          find rskj-core/build/test-results -type f -name "*.xml" -exec cp {} ~/junit/ \;
+        if: always()
+
+  mining-tests:
+    needs: tests
+    runs-on: ubuntu-latest
+    container:
+      image: alpine:3.10
+    defaults:
+        run:
+            working-directory: .
+    steps:
+      - name: Setup System Tools
+        run: |
+          apt update -y
+          apt install -y curl jq
+
+      - name: Get Gradle jar
+        run: |
+          ./configure.sh
+
+      - name: Mining integration tests
+        run: |
+          wait_for_completion() {
+            # inspired from https://discuss.circleci.com/t/waiting-for-build-to-complete-when-invoked-via-http-api/14989
+            build_number=$1
+            poll_interval=60
+  
+            i=0
+            max_count=20
+            while [ $i -lt $max_count ]; do
+              # output to avoid CircleCI considering the job stuck
+              res=$(curl -Ssfu "$CIRCLE_INTEGRATIONS_TOKENS:" \
+                  "https://circleci.com/api/v1.1/project/github/$MIT_ORGANIZATION/$MIT_PROJECT/$build_number" \
+                  | jq -r '[.lifecycle, .outcome] | @tsv')
+              IFS="	" set -- $res
+              lifecycle=${1:-}
+              outcome=${2:-}
+              if [ "$lifecycle" = "queued" ]; then
+                printf "Build is enqueued. Waiting...\n"
+                # don't increment $i
+              else
+                printf "[%02u/%02u] Waiting for build %s ...\n" \
+                    "$i" "$max_count" "$build_url"
+                i=$(($i + 1))
+              fi
+              if [ "$lifecycle" = "finished" ]; then
+                printf "Build %u finished. Outcome: \"%s\".\n" \
+                    "$build_number" "$outcome"
+                # return success iff job outcome is "success"
+                test "$outcome" = "success"
+                return $?
+              fi
+
+              sleep $poll_interval
+            done
+            return 1
+          }
+
+          json_payload='{
+            "build_parameters": {
+              "RSKJ_CIRCLE_BRANCH": "'$CIRCLE_BRANCH'",
+              "RSKJ_CIRCLE_USERNAME": "'$CIRCLE_PROJECT_USERNAME'",
+              "RSKJ_CIRCLE_REPONAME": "'$CIRCLE_PROJECT_REPONAME'",
+              "RSKJ_PR_NUMBER": "'$CIRCLE_PR_NUMBER'",
+              "RSKJ_CIRCLE_SHA1": "'$CIRCLE_SHA1'"
+            }
+          }'
+          res=$(curl -Ssf -u "$CIRCLE_INTEGRATIONS_TOKEN:" \
+              -H "Content-type: application/json" -d "$json_payload" \
+              "https://circleci.com/api/v1.1/project/github/$MIT_ORGANIZATION/$MIT_PROJECT/tree/$MIT_BRANCH" \
+              | jq -r '[.build_url, .build_num] | @tsv')
+          IFS="	" set -- $res
+          test $# -eq 2 # ensure exactly 2 values are expanded
+          build_url=$1
+          build_num=$2
+          printf "Running mining integration tests. Follow it on:\n\n    %s\n\n" "$build_url"
+          sleep 10 # give CircleCI some time to spin up the job
+          wait_for_completion "$build_num"