Added rule for "_" suffix for internal variables

README.md

@@ -41,6 +41,9 @@ In the .soliumrc.json file, add:
         ],
         "zeppelin/no-unused-imports": [
           "warning"
+        ],
+        "zeppelin/internal-state-underscore-suffix": [
+          "warning"
         ]
     }
 

index.js

@@ -17,6 +17,7 @@ module.exports = {
         "no-arithmetic-operations": require("./rules/no-arithmetic-operations"),
         "no-state-variable-shadowing": require("./rules/no-state-variable-shadowing"),
         "no-unchecked-send": require("./rules/no-unchecked-send"),
-        "no-unused-imports": require("./rules/no-unused-imports")
+        "no-unused-imports": require("./rules/no-unused-imports"),
+        "internal-state-underscore-suffix": require("./rules/internal-state-underscore-suffix")
     }
 };

rules/internal-state-underscore-suffix.js

@@ -0,0 +1,38 @@
+/**
+ * @fileoverview Report internal state variables without underscore suffix.
+ */
+
+"use strict";
+
+module.exports = {
+    meta: {
+        docs: {
+            recommended: true,
+            type: "error",
+            description: "Report internal state variables without underscore suffix"
+        },
+        schema: []
+    },
+
+    create: function(context) {
+
+        function inspectStateVariableDeclaration(emitted) {
+            if (emitted.exit) {
+                return;
+            }
+
+            if ( (param.id.charAt(param.id.length - 1) !== "_") &&
+               (param.visibility != "public")) {
+                context.report({
+                    node: emitted.node,
+                    message: `'${param.id}' does not have an underscore as suffix.`
+                });
+            }
+
+        }
+
+        return {
+            StateVariableDeclaration: inspectStateVariableDeclaration
+        };
+    }
+};

test/internal-state-underscore-suffix.js

@@ -0,0 +1,65 @@
+/**
+ * @fileoverview Tests for internal-state-underscore-suffix rule
+ */
+
+"use strict";
+
+const dedent = require("dedent");
+const Solium = require("solium");
+const wrappers = require("./utils/wrappers");
+const addPragma = wrappers.addPragma;
+
+const userConfig = {
+    rules: {
+        "zeppelin/internal-state-underscore-suffix": 1
+    }
+};
+
+describe("[RULE] internal-state-underscore-suffix: Rejections", function() {
+
+    afterEach(function(done) {
+        Solium.reset();
+        done();
+    });
+
+    it("should reject internal state variables without underscore suffix", function(done) {
+        const code = dedent`
+            contract TestContract {
+
+                bool internal_no_underscore_suffix = false;
+
+                function testFunction(uint parameter) {}
+            }`,
+            errors = Solium.lint(addPragma(code), userConfig);
+
+        errors.should.be.instanceof(Array);
+        errors.length.should.equal(1);
+        errors[0].message.should.equal(
+            "'internal_no_underscore_suffix' does not have an underscore suffix.");
+        done();
+    });
+});
+
+describe("[RULE] internal-state-underscore-suffix: Acceptances", function() {
+
+    afterEach(function(done) {
+        Solium.reset();
+        done();
+    });
+
+    it("should accept internal state variables with underscore suffix", function(done) {
+        const code = dedent`
+            contract TestContract {
+
+                bool public internal_underscore_suffix_ = false;
+
+                function testFunction(uint parameter) {}
+            }`,
+            errors = Solium.lint(addPragma(code), userConfig);
+
+        errors.should.deepEqual([]);
+
+        done();
+    });
+
+});