add more openzeppelin-solidity library contracts

test/library/Math.test.js

@@ -0,0 +1,43 @@
+var MathMock = artifacts.require('MathMock');
+
+contract('Math', function (accounts) {
+  let math;
+
+  before(async function () {
+    math = await MathMock.new();
+  });
+
+  it('returns max64 correctly', async function () {
+    let a = 5678;
+    let b = 1234;
+    await math.max64(a, b);
+    let result = await math.result64();
+    assert.equal(result, a);
+  });
+
+  it('returns min64 correctly', async function () {
+    let a = 5678;
+    let b = 1234;
+    await math.min64(a, b);
+    let result = await math.result64();
+
+    assert.equal(result, b);
+  });
+
+  it('returns max256 correctly', async function () {
+    let a = 5678;
+    let b = 1234;
+    await math.max256(a, b);
+    let result = await math.result256();
+    assert.equal(result, a);
+  });
+
+  it('returns min256 correctly', async function () {
+    let a = 5678;
+    let b = 1234;
+    await math.min256(a, b);
+    let result = await math.result256();
+
+    assert.equal(result, b);
+  });
+});