all fibonacci tests passing

src/fibonacci.js

@@ -0,0 +1,18 @@
+export default function fibonacci(input) {
+
+  const fibArray = [0, 1]
+
+  if (!Number.isInteger(input) || input < 1) {
+    return undefined
+  } else if (input === 1) {
+    return [0]
+  } else if (input === 2) {
+    return fibArray
+  } else {
+    for (let i = 2; i < input; i++) {
+      let current = fibArray[i - 1] + fibArray[i - 2]
+      fibArray.push(current)
+    }
+  }
+  return fibArray
+}

test/fibonacci_test.js

@@ -0,0 +1,26 @@
+import { expect } from 'chai';
+import fibonacci from '../src/fibonacci';
+
+describe.only('fibonacci()', () => {
+  it('should be a function', () => {
+    expect(fibonacci).to.be.a('function');
+  });
+
+  it('should output an array', () => {
+    expect(fibonacci(1)).to.be.a('array');
+  });
+
+  it('should give a proper array', () => {
+    expect(fibonacci(10)).to.deep.equal([0, 1, 1, 2, 3, 5, 8, 13, 21, 34]);
+  });
+
+  it('should not try to run the function with the values of empty things', () => {
+    expect(fibonacci({})).to.equal(undefined);
+    expect(fibonacci('')).to.equal(undefined);
+    expect(fibonacci([])).to.equal(undefined);
+  });
+
+  it('should not let you plug in negitive integers', () => {
+    expect(fibonacci(-5)).to.equal(undefined);
+  });
+});