merkle-tree

Using Nix

Nix

Nix is a package manager that goes beyond traditional ones (like Apt, NPM, Brew, etc.) as it allows:

• full reproducibility (the same input guarantee to give exactly the same output)
• "local" packages, meaning you don't need to install globally
• describe in a Nix file everything you need to build or run an application, and Nix configures everything locally:
  • language dependencies like JDK 14 or GHC 8.10.7
  • build systems like Maven or Stack
  • system dependencies like Zlib or PostgreSQL
  • environment variables
  • etc.

Below is a high-level explanation of the different Nix files.

Run the project

There is no executable, only a test suite is available. To execute them, simply run:

# First, you need to enter the nix-shell to get `stack` available
$ nix-shell
# Then you run the tests
[nix-shell:~/projects/merkle-tree]$ stack test

Modifying tests

At the beginning of MerkleSpec there are some Text which are the SHA256 hex representation of poorly chose values:

anyValidData :: Text
anyValidData = "c67579305b91024bf849d4769c3110fac3f2d18678f20364e8f8b961cfcc8758" --Hex representation of "anyValidData"

anyValidDataBis :: Text
anyValidDataBis = "63976e06e21e475d03e227a04223293eb300b682dff506f5abbf981505bef520" --Hex representation of "anyValidDataBis"

anyValidDataTer :: Text
anyValidDataTer = "b3981997f43c7c06b8840f222e5789503982954b21fcb1b78ad4c27a246f8597" --Hex representation of "anyValidDataTer"

anyValidDataQuater :: Text
anyValidDataQuater = "9cc3cdb9ae29e2c2ae606601fccd546c4b767e7a07d5f8353f40484b20067304" --Hex representation of "anyValidDataQuater"

anyValidDataQuinquies :: Text
anyValidDataQuinquies = "d17f257be7cab8937bb0c063456156fae4a90362a6a5774faf7f0eec63028450" --Hex representation of "anyValidDataQuinquies"

If you want to run the tests with different values, you can:

• Change the Hex value of these constants:

anyValidData :: Text
anyValidData = "04fde3471765d709f60613c849bcc0726cd6d666fb871bc0acde28dbe227a1e8" --Hex representation of "myCustomData"

• Create new constants using new Hex value and use them in test suite:

-- Module Commons
myCustomData :: Text
myCustomData = "04fde3471765d709f60613c849bcc0726cd6d666fb871bc0acde28dbe227a1e8" --Hex representation of "myCustomData"

myCustomDataBis :: Text
myCustomDataBis = "a379aac97a52d544f357599fa2b2d344291797f577f79bd1861d1e0b71c6a682" --Hex representation of "myCustomDataBis"

-- Module MerkleSpec
merkleSpec :: Spec
merkleSpec = do
  describe "TESTING: Merkle.combine" $
    it "combines two Digest SHA256" $ do
      let [digest1, digest2, mkr] =
            fromJust . parseSHA256
              <$> [ myCustomData,
                    myCustomDataBis, --anyValidDataBis
                    "4f7333e0a41d00da0abac20e4a4c3b5485ade6b74c7a766b1a6d334c23cc870c"
                  ]
      SUT.combine digest1 digest2 `shouldBe` mkr

Of course, if you don't change the mkr Hex value ("4f7333e0a41d00da0abac20e4a4c3b5485ade6b74c7a766b1a6d334c23cc870c" in our example), the test will fail: