Support modifiers

lib/modules/coverage/contract_source.js

@@ -128,6 +128,7 @@ class ContractSource {
         case 'Assignment':
         case 'EventDefinition':
         case 'Literal':
+        case 'PlaceholderStatement':
         case 'PragmaDirective':
         case 'VariableDeclaration':
           // We don't need to do anything with these. Just carry on.
@@ -207,6 +208,7 @@ class ContractSource {
           children = node.nodes;
           break;
 
+        case 'ModifierDefinition':
         case 'FunctionDefinition':
           // Istanbul only wants the function definition, not the body, so we're
           // going to do some fun math here.

test_apps/coverage_app/contracts/modifiers.sol

@@ -0,0 +1,25 @@
+pragma solidity ^0.4.23;
+
+contract Modifiers {
+  uint public storedData;
+
+  constructor(uint initialValue) public {
+    storedData = initialValue;
+  }
+
+  modifier upTo(uint amount, uint desired) {
+    require(
+      desired <= amount,
+      "Value is too high."
+    );
+    _;
+  }
+
+  function set(uint x) public upTo(1000, x) {
+    storedData = x;
+  }
+
+  function get() public view returns (uint retVal) {
+    return storedData;
+  }
+}

test_apps/coverage_app/test/modifiers_spec.js

@@ -0,0 +1,34 @@
+/*global contract, config, it, assert*/
+const Modifiers = require('Embark/contracts/Modifiers');
+
+config({
+  contracts: {
+    "Modifiers": {
+      args: [100]
+    }
+  }
+});
+
+contract("Modifiers", function() {
+  it("should set constructor value", function(done) {
+    Modifiers.methods.storedData().call().then((result) => {
+      assert.strictEqual(parseInt(result, 10), 100);
+      done();
+    });
+  });
+
+  it("set storage value when valid", function(done) {
+    Modifiers.methods.set(150).send().then(() => {
+      Modifiers.methods.get().call().then((result) => {
+        assert.strictEqual(parseInt(result, 10), 150);
+        done();
+      });
+    });
+  });
+
+  it("refuses storage value when invalid", function(done) {
+    Modifiers.methods.set(10000).send().catch((_err) => {
+      done();
+    });
+  });
+});