diff --git a/apps/contribution/contracts/Contribution.sol b/apps/contribution/contracts/Contribution.sol
index 89bdfc7..f98e4b8 100644
--- a/apps/contribution/contracts/Contribution.sol
+++ b/apps/contribution/contracts/Contribution.sol
@@ -152,6 +152,8 @@ contract Contribution is AragonApp {
 
   function add(uint32 amount, uint32 contributorId, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize) public isInitialized auth(ADD_CONTRIBUTION_ROLE) {
     //require(canPerform(msg.sender, ADD_CONTRIBUTION_ROLE, new uint32[](0)), 'nope');
+    require(amount > 0, "INVALID_AMOUNT");
+
     uint32 contributionId = contributionsCount + 1;
     ContributionData storage c = contributions[contributionId];
     c.exists = true;
diff --git a/apps/contribution/contracts/test/Spoof.sol b/apps/contribution/contracts/test/Spoof.sol
new file mode 100644
index 0000000..dba6388
--- /dev/null
+++ b/apps/contribution/contracts/test/Spoof.sol
@@ -0,0 +1,18 @@
+pragma solidity ^0.4.24;
+
+import "@aragon/os/contracts/acl/ACL.sol";
+import "@aragon/os/contracts/kernel/Kernel.sol";
+import "@aragon/os/contracts/factory/DAOFactory.sol";
+import "../../../contributor/contracts/Contributor.sol";
+import "../../../token/contracts/Token.sol";
+
+// You might think this file is a bit odd, but let me explain.
+// We only use for now those imported contracts in our tests, which
+// means Truffle will not compile them for us, because they are from
+// an external dependency.
+
+
+// solium-disable-next-line no-empty-blocks
+contract Spoof {
+  // ...
+}
diff --git a/apps/contribution/test/app.js b/apps/contribution/test/app.js
deleted file mode 100644
index bb9f094..0000000
--- a/apps/contribution/test/app.js
+++ /dev/null
@@ -1,5 +0,0 @@
-// const Contribution = artifacts.require('Contribution.sol');
-
-contract('Contribution', (_accounts) => {
-  it('should be tested');
-});
diff --git a/apps/contribution/test/contribution.js b/apps/contribution/test/contribution.js
new file mode 100644
index 0000000..53059fe
--- /dev/null
+++ b/apps/contribution/test/contribution.js
@@ -0,0 +1,231 @@
+const namehash = require('ethers').utils.namehash;
+
+// eslint-disable-next-line no-undef
+const Contribution = artifacts.require("Contribution.sol");
+// eslint-disable-next-line no-undef
+const Contributor = artifacts.require("Contributor.sol");
+// eslint-disable-next-line no-undef
+const Token = artifacts.require("Token.sol");
+
+// eslint-disable-next-line no-undef
+const getContract = name => artifacts.require(name);
+const { assertRevert } = require('@aragon/test-helpers/assertThrow');
+
+const ZERO_ADDR = '0x0000000000000000000000000000000000000000';
+
+contract('Contribution app', (accounts) => {
+  let kernelBase, aclBase, daoFactory, r, dao, acl, contribution, token, contributor;
+
+  const root = accounts[0];
+  const member1 = accounts[1];
+
+  // eslint-disable-next-line no-undef
+  before(async () => {
+    kernelBase = await getContract('Kernel').new(true); // petrify immediately
+    aclBase = await getContract('ACL').new();
+    daoFactory = await getContract('DAOFactory').new(kernelBase.address, aclBase.address, ZERO_ADDR);
+    r = await daoFactory.newDAO(root);
+    dao = getContract('Kernel').at(r.logs.filter(l => l.event == 'DeployDAO')[0].args.dao);
+    acl = getContract('ACL').at(await dao.acl());
+
+    //create dao mamnager permission for coin owner
+    await acl.createPermission(
+      root,
+      dao.address,
+      await dao.APP_MANAGER_ROLE(),
+      root,
+      { from: root }
+    );
+
+    //apps id
+    let appsId = [];
+    appsId[0] = namehash("kredits-contribution");
+    appsId[1] = namehash("kredits-contributor");
+    appsId[2] = namehash("kredits-proposal");
+    appsId[3] = namehash("kredits-token");
+
+
+    //get new app instance from DAO
+    let receipt = await dao.newAppInstance(
+      appsId[0],
+      (await Contribution.new()).address,
+      0x0,
+      false,
+      { from: root }
+    );
+    contribution = Contribution.at(
+      receipt.logs.filter(l => l.event == 'NewAppProxy')[0].args.proxy
+    );
+
+    receipt = await dao.newAppInstance(
+      appsId[3],
+      (await Token.new()).address,
+      0x0,
+      false,
+      { from: root }
+    );
+    token = Token.at(
+      receipt.logs.filter(l => l.event == 'NewAppProxy')[0].args.proxy
+    );
+
+    receipt = await dao.newAppInstance(
+      appsId[1],
+      (await Contributor.new()).address,
+      0x0,
+      false,
+      { from: root }
+    );
+    contributor = Contributor.at(
+      receipt.logs.filter(l => l.event == 'NewAppProxy')[0].args.proxy
+    );
+
+    //init app
+    await contribution.initialize(appsId);
+
+    await acl.createPermission(
+      root,
+      contribution.address,
+      await contribution.ADD_CONTRIBUTION_ROLE(),
+      root,
+      { from: root }
+    );
+
+    await acl.createPermission(
+      root,
+      contribution.address,
+      await contribution.VETO_CONTRIBUTION_ROLE(),
+      root,
+      { from: root }
+    );
+
+    //init token (app)
+    await token.initialize(appsId);
+
+    //create token mint permission for coin owner
+    await acl.createPermission(
+      contribution.address,
+      token.address,
+      await token.MINT_TOKEN_ROLE(),
+      root,
+      { from: root }
+    );
+
+    //init contributor app
+    await contributor.initialize(root, appsId);
+
+    await acl.createPermission(
+      root,
+      contributor.address,
+      await contributor.MANAGE_CONTRIBUTORS_ROLE(),
+      root,
+      { from: root }
+    );
+  });
+
+  describe("Owner default space permissions", async () => {
+    it('check owner can add contribution', async () => {
+      let addContributionPermission = await acl.hasPermission(root, contribution.address, await contribution.ADD_CONTRIBUTION_ROLE());
+      // eslint-disable-next-line no-undef
+      assert.equal(addContributionPermission, true);
+    });
+
+    it('check owner can veto contribution', async () => {
+      let vetoContributionPermission = await acl.hasPermission(root, contribution.address, await contribution.VETO_CONTRIBUTION_ROLE());
+      // eslint-disable-next-line no-undef
+      assert.equal(vetoContributionPermission, true);
+    });
+
+    it('check contribution app can mint token', async () => {
+      let mintTokenPermission = await acl.hasPermission(contribution.address, token.address, await token.MINT_TOKEN_ROLE());
+      // eslint-disable-next-line no-undef
+      assert.equal(mintTokenPermission, true);
+    });
+  });
+
+  describe("Add contribution", async () => {
+    let amount = 100;
+    let contributorId = 1;
+    let hashDigest = '0x0000000000000000000000000000000000000000000000000000000000000000';
+    let hashFunction = 1;
+    let hashSize = 1;
+
+    it("should revert when add contribution from address that does not have permission", async () => {
+      return assertRevert(async () => {
+        await contribution.add(amount, contributorId, hashDigest, hashFunction, hashSize, {from: member1});
+        'sender does not have permission';
+      });
+    });
+
+    it("should revert when add contribution with amount equal to zero", async () => {
+      return assertRevert(async () => {
+        await contribution.add(0, contributorId, hashDigest, hashFunction, hashSize, {from: root});
+        'amount equal to zero';
+      });
+    });
+
+    it("add contribution", async () => {
+      let contributionCountBefore = await contribution.contributionsCount();
+      await contribution.add(amount, contributorId, hashDigest, hashFunction, hashSize, {from: root});
+      let contributionCountAfter = await contribution.contributionsCount();
+      // eslint-disable-next-line no-undef
+      assert.equal(contributionCountAfter.toNumber()-contributionCountBefore.toNumber(), 1);
+      let contributionObject = await contribution.getContribution(contributionCountAfter.toNumber());
+      // eslint-disable-next-line no-undef
+      assert.equal(contributionObject[1], contributorId);
+      let isExist = await contribution.exists(contributionCountAfter.toNumber());
+      // eslint-disable-next-line no-undef
+      assert.equal(isExist, true);
+    });
+  });
+
+  describe("Veto/Claim contribution", async () => {
+
+    it("should revert when veto from address that does not have permission", async () => {
+      let contributionId = await contribution.contributionsCount();
+      return assertRevert(async () => {
+        await contribution.veto(contributionId.toNumber(), {from: member1});
+        'sender does not have permission to veto';
+      });
+    });
+
+    it("should revert when veto contribution that does not exist", async () => {
+      let contributionId = await contribution.contributionsCount();
+      return assertRevert(async () => {
+        await contribution.veto(contributionId.toNumber()+1, {from: root});
+        'contribution not found';
+      });
+    });
+
+    it("should revert when claim contribution that does not exist", async () => {
+      let contributionId = await contribution.contributionsCount();
+      return assertRevert(async () => {
+        await contribution.claim(contributionId.toNumber()+1, {from: root});
+        'contribution not found';
+      });
+    });
+
+    it("claim contribution", async () => {
+      let contributionId = await contribution.contributionsCount();
+      await contribution.claim(contributionId);
+      let contributionObject = await contribution.getContribution(contributionId.toNumber());
+      // eslint-disable-next-line no-undef
+      assert(contributionObject[3], true);
+    });
+
+    it("should revert when claim already claimed contribution", async () => {
+      let contributionId = await contribution.contributionsCount();
+      return assertRevert(async () => {
+        await contribution.claim(contributionId.toNumber(), {from: root});
+        'contribution already claimed';
+      });
+    });
+
+    it("should revert when veto already claimed contribution", async () => {
+      let contributionId = await contribution.contributionsCount();
+      return assertRevert(async () => {
+        await contribution.veto(contributionId.toNumber(), {from: root});
+        'contribution already claimed';
+      });
+    });
+  });
+});