Tests cleanup (#53)

General test improvements.
- Simplifies Dockerfile
- Refactors tests so they can be run independently

Co-authored-by: Roy Crihfield <roy@manteia.ltd>
Co-authored-by: Prathamesh Musale <prathamesh.musale0@gmail.com>
Reviewed-on: cerc-io/laconic-sdk#53
Reviewed-by: Thomas E Lackey <telackey@noreply.git.vdb.to>
Co-authored-by: Prathamesh Musale <prathamesh@noreply.git.vdb.to>
Co-committed-by: Prathamesh Musale <prathamesh@noreply.git.vdb.to>

Dockerfile

@@ -0,0 +1,38 @@
+# Originally from: https://github.com/devcontainers/images/blob/main/src/javascript-node/.devcontainer/Dockerfile
+# [Choice] Node.js version (use -bullseye variants on local arm64/Apple Silicon): 18, 16, 14, 18-bullseye, 16-bullseye, 14-bullseye, 18-buster, 16-buster, 14-buster
+ARG VARIANT=16-bullseye
+FROM node:${VARIANT}
+
+ARG USERNAME=node
+ARG NPM_GLOBAL=/usr/local/share/npm-global
+
+# Add NPM global to PATH.
+ENV PATH=${NPM_GLOBAL}/bin:${PATH}
+
+RUN \
+    # Configure global npm install location, use group to adapt to UID/GID changes
+    if ! cat /etc/group | grep -e "^npm:" > /dev/null 2>&1; then groupadd -r npm; fi \
+    && usermod -a -G npm ${USERNAME} \
+    && umask 0002 \
+    && mkdir -p ${NPM_GLOBAL} \
+    && touch /usr/local/etc/npmrc \
+    && chown ${USERNAME}:npm ${NPM_GLOBAL} /usr/local/etc/npmrc \
+    && chmod g+s ${NPM_GLOBAL} \
+    && npm config -g set prefix ${NPM_GLOBAL} \
+    && su ${USERNAME} -c "npm config -g set prefix ${NPM_GLOBAL}" \
+    # Install eslint
+    && su ${USERNAME} -c "umask 0002 && npm install -g eslint" \
+    && npm cache clean --force > /dev/null 2>&1
+
+WORKDIR /
+COPY entrypoint.sh .
+ENTRYPOINT ["/entrypoint.sh"]
+CMD node --version
+
+WORKDIR /app/laconic-sdk
+
+COPY package*.json .
+RUN yarn install
+COPY . .
+
+WORKDIR /app/laconic-sdk