Remove Math.min64 and Math.max64 (#1156)

* remove Math.min64 and Math.max64

* refactor Math tests to use return values

* enhance Math coverage

contracts/math/Math.sol

@@ -6,19 +6,11 @@ pragma solidity ^0.4.24;
  * @dev Assorted math operations
  */
 library Math {
-  function max64(uint64 _a, uint64 _b) internal pure returns (uint64) {
+  function max(uint256 _a, uint256 _b) internal pure returns (uint256) {
     return _a >= _b ? _a : _b;
   }
 
-  function min64(uint64 _a, uint64 _b) internal pure returns (uint64) {
-    return _a < _b ? _a : _b;
-  }
-
-  function max256(uint256 _a, uint256 _b) internal pure returns (uint256) {
-    return _a >= _b ? _a : _b;
-  }
-
-  function min256(uint256 _a, uint256 _b) internal pure returns (uint256) {
+  function min(uint256 _a, uint256 _b) internal pure returns (uint256) {
     return _a < _b ? _a : _b;
   }
 }

contracts/mocks/MathMock.sol

@@ -5,22 +5,11 @@ import "../../contracts/math/Math.sol";
 
 
 contract MathMock {
-  uint64 public result64;
-  uint256 public result256;
-
-  function max64(uint64 _a, uint64 _b) public {
-    result64 = Math.max64(_a, _b);
-  }
-
-  function min64(uint64 _a, uint64 _b) public {
-    result64 = Math.min64(_a, _b);
-  }
-
-  function max256(uint256 _a, uint256 _b) public {
-    result256 = Math.max256(_a, _b);
+  function max(uint256 _a, uint256 _b) public pure returns (uint256) {
+    return Math.max(_a, _b);
   }
 
-  function min256(uint256 _a, uint256 _b) public {
-    result256 = Math.min256(_a, _b);
+  function min(uint256 _a, uint256 _b) public pure returns (uint256) {
+    return Math.min(_a, _b);
   }
 }

test/library/Math.test.js

@@ -1,43 +1,34 @@
 const MathMock = artifacts.require('MathMock');
 
 contract('Math', function () {
-  let math;
+  const min = 1234;
+  const max = 5678;
 
   beforeEach(async function () {
-    math = await MathMock.new();
+    this.math = await MathMock.new();
   });
 
-  it('returns max64 correctly', async function () {
-    const a = 5678;
-    const b = 1234;
-    await math.max64(a, b);
-    const result = await math.result64();
-    assert.equal(result, a);
-  });
-
-  it('returns min64 correctly', async function () {
-    const a = 5678;
-    const b = 1234;
-    await math.min64(a, b);
-    const result = await math.result64();
-
-    assert.equal(result, b);
-  });
+  describe('max', function () {
+    it('is correctly detected in first argument position', async function () {
+      const result = await this.math.max(max, min);
+      assert.equal(result, max);
+    });
 
-  it('returns max256 correctly', async function () {
-    const a = 5678;
-    const b = 1234;
-    await math.max256(a, b);
-    const result = await math.result256();
-    assert.equal(result, a);
+    it('is correctly detected in second argument position', async function () {
+      const result = await this.math.max(min, max);
+      assert.equal(result, max);
+    });
   });
 
-  it('returns min256 correctly', async function () {
-    const a = 5678;
-    const b = 1234;
-    await math.min256(a, b);
-    const result = await math.result256();
+  describe('min', function () {
+    it('is correctly detected in first argument position', async function () {
+      const result = await this.math.min(min, max);
+      assert.equal(result, min);
+    });
 
-    assert.equal(result, b);
+    it('is correctly detected in second argument position', async function () {
+      const result = await this.math.min(max, min);
+      assert.equal(result, min);
+    });
   });
 });