`ogma-core`: Fix translation of equivalence boolean operator from SMV. Refs #126.

[ivanperez-keera]

Replace the translation of the equivalence operator from SMV to be (==) in Copilot, as prescribed in the solution proposed for #126.

[ivanperez-keera]

Change Manager: Verified that:

• Solution is implemented:

  • [X] The code proposed compiles passes the tests. Details: Docker image:

    
    FROM ubuntu:trusty

  RUN apt-get update

  RUN apt-get install --yes software-properties-common RUN add-apt-repository ppa:hvr/ghc RUN apt-get update

  RUN apt-get install --yes ghc-8.6.5 cabal-install-2.4 RUN apt-get install --yes libz-dev

  ENV PATH=/opt/ghc/8.6.5/bin:/opt/cabal/2.4/bin:$PWD/.cabal-sandbox/bin:$PATH

  RUN cabal update RUN cabal v1-sandbox init RUN cabal v1-install alex happy RUN apt-get install --yes git

  We install the application first and then test it, in case any tests need to

  run the tool.

  CMD git clone $REPO && \ cd $NAME && \ git checkout $COMMIT && \ cd .. && \ cabal v1-install $NAME/$PAT/ --enable-tests && \ cabal v1-install $NAME/$PAT/ --enable-tests --run-tests -j1

  Command:
  ```sh
  $ docker run -e "REPO=https://github.com/nasa/ogma" -e "NAME=ogma" -e PAT="ogma-" -e "COMMIT=d3ebffca2227cd61e1ea3e520fb5610f487e3633" -it ogma-test

  • [X] The solution proposed fixes the issues described. Details: The following Dockerfile uses the spec containing an equivalence operator in the SMV property, and it compiles the resulting Copilot code.

    
    --- Dockerfile-verify-126
    FROM ubuntu:trusty

  ENV DEBIAN_FRONTEND=noninteractive

  RUN apt-get update

  RUN apt-get install --yes software-properties-common RUN add-apt-repository ppa:hvr/ghc RUN apt-get update

  RUN apt-get install --yes ghc-8.6.5 cabal-install-2.4 RUN apt-get install --yes libz-dev

  ENV PATH=/opt/ghc/8.6.5/bin:/opt/cabal/2.4/bin:$PWD/.cabal-sandbox/bin:$PATH

  RUN cabal update RUN cabal v1-sandbox init RUN cabal v1-install alex happy RUN cabal v1-install copilot-3.18.1 RUN apt-get install --yes git

  ADD reqs.json /tmp/reqs.json

  CMD git clone $REPO && \ cd $NAME && \ git checkout $COMMIT && \ cd .. && \ cabal v1-install $NAME/$PAT**/ && \ ogma fret-component-spec --fret-file-name /tmp/reqs.json > CS.hs && \ cabal v1-exec -- ghc --make CS.hs && \ echo "Success"

  --- reqs.json { "test_spec": { "Functions": [ ], "Internal_variables": [ ], "Other_variables": [ { "name": "a", "type": "bool" } ], "Requirements": [ { "CoCoSpecCode": "true", "fretish": "unimportant", "name": "testCopilot001", "ptLTL": "a <-> a" } ] } }

  Command:
  ```sh
  $ docker run -e "REPO=https://github.com/nasa/ogma" -e "NAME=ogma" -e PAT="ogma-" -e "COMMIT=d3ebffca2227cd61e1ea3e520fb5610f487e3633" -it ogma-verify-126

• [X] Implementation is documented. Details: No changes needed.
• [X] Change history is clear.
• [X] Commit messages are clear.
• [X] Changelogs are updated.
• [X] Examples are updated. Details: No examples affected.
• [X] Required version bumps are evaluated. Details: No bump needed (internal change).