Introduce directory contract (#102)

packages/contracts/contracts/Directory.sol

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+pragma solidity ^0.8.5;
+
+contract Directory {
+    address public votingContract;
+
+    address[] public communities;
+    mapping(address => uint256) private communitiesIdx;
+
+    constructor(address _votingContract) {
+        votingContract = _votingContract;
+    }
+
+    function isCommunityInDirectory(address community) public view returns (bool) {
+        return communitiesIdx[community] > 0;
+    }
+
+    function getCommunities() public view returns (address[] memory) {
+        return communities;
+    }
+
+    modifier onlyVotingContract() {
+        require(msg.sender == votingContract, 'Invalid sender');
+        _;
+    }
+
+    function addCommunity(address community) public onlyVotingContract {
+        require(communitiesIdx[community] == 0, 'Community already exist');
+        communities.push(community);
+        communitiesIdx[community] = communities.length;
+    }
+
+    function removeCommunity(address community) public onlyVotingContract {
+        uint256 index = communitiesIdx[community];
+        if (index == 0) return;
+        index--;
+        if (communities.length > 1) {
+            communities[index] = communities[communities.length - 1];
+            communitiesIdx[communities[index]] = index + 1;
+        }
+        communities.pop();
+        communitiesIdx[community] = 0;
+    }
+}

packages/contracts/test/2.directory.test.ts

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+import { expect, use } from 'chai'
+import { loadFixture, deployContract, solidity } from 'ethereum-waffle'
+import Directory from '../build/Directory.json'
+
+use(solidity)
+
+describe('directory contract', () => {
+  const communities = [
+    '0xAcdd71e5Ef3Ab3356d62da78A941aAc08a18CF2b',
+    '0xF1B65D4b7e5D6aE45c66Bc015e2556f228A6968f',
+    '0xadd590e785c0Da8B7A39A344e76fCF02193b3641',
+  ]
+  async function fixture([alice, bob]: any[], provider: any) {
+    const contract = await deployContract(alice, Directory, [alice.address])
+    return { contract, alice, bob, provider }
+  }
+
+  it('deploys', async () => {
+    const { contract, alice } = await loadFixture(fixture)
+    expect(await contract.votingContract()).to.eq(alice.address)
+  })
+
+  it('adds community', async () => {
+    const { contract } = await loadFixture(fixture)
+    await contract.addCommunity(communities[0])
+    expect(await contract.getCommunities()).to.deep.eq([communities[0]])
+    await contract.addCommunity(communities[1])
+    expect(await contract.getCommunities()).to.deep.eq([communities[0], communities[1]])
+  })
+
+  it('only owner can add', async () => {
+    const { contract, bob } = await loadFixture(fixture)
+    const bobContract = contract.connect(bob)
+    await expect(bobContract.addCommunity(communities[0])).to.be.revertedWith('Invalid sender')
+    expect(await contract.getCommunities()).to.deep.eq([])
+  })
+
+  it('only owner can remove', async () => {
+    const { contract, bob } = await loadFixture(fixture)
+    await contract.addCommunity(communities[0])
+    const bobContract = contract.connect(bob)
+    await expect(bobContract.removeCommunity(communities[0])).to.be.revertedWith('Invalid sender')
+    expect(await contract.getCommunities()).to.deep.eq([communities[0]])
+  })
+
+  it('removes community', async () => {
+    const { contract } = await loadFixture(fixture)
+    await contract.addCommunity(communities[0])
+    await contract.addCommunity(communities[1])
+    await contract.addCommunity(communities[2])
+    await contract.removeCommunity(communities[1])
+    expect(await contract.getCommunities()).to.deep.eq([communities[0], communities[2]])
+  })
+
+  it("can't add duplicate", async () => {
+    const { contract } = await loadFixture(fixture)
+    await contract.addCommunity(communities[0])
+    await expect(contract.addCommunity(communities[0])).to.be.revertedWith('Community already exist')
+    expect(await contract.getCommunities()).to.deep.eq([communities[0]])
+  })
+
+  it('community in directory', async () => {
+    const { contract } = await loadFixture(fixture)
+    await contract.addCommunity(communities[0])
+
+    expect(await contract.isCommunityInDirectory(communities[0])).to.eq(true)
+    expect(await contract.isCommunityInDirectory(communities[1])).to.eq(false)
+  })
+})