1 files changed, 49 insertions, 0 deletions
diff --git a/date-fns/src/setDate/test.ts b/date-fns/src/setDate/test.ts
new file mode 100644
index 0000000..7c07ff5
--- /dev/null
+++ b/date-fns/src/setDate/test.ts
@@ -0,0 +1,49 @@
+// @flow
+/* eslint-env mocha */
+
+import assert from 'power-assert'
+import setDate from '.'
+
+describe('setDate', function() {
+  it('sets the day of the month', function() {
+    const result = setDate(new Date(2014, 8 /* Sep */, 1), 30)
+    assert.deepEqual(result, new Date(2014, 8 /* Sep */, 30))
+  })
+
+  it('accepts a timestamp', function() {
+    const result = setDate(new Date(2014, 8 /* Sep */, 1).getTime(), 25)
+    assert.deepEqual(result, new Date(2014, 8 /* Sep */, 25))
+  })
+
+  it('converts a fractional number to an integer', function() {
+    const result = setDate(new Date(2014, 8 /* Sep */, 1), 30.3)
+    assert.deepEqual(result, new Date(2014, 8 /* Sep */, 30))
+  })
+
+  it('implicitly converts number arguments', function() {
+    // @ts-expect-error
+    const result = setDate(new Date(2014, 8 /* Sep */, 1), '30')
+    assert.deepEqual(result, new Date(2014, 8 /* Sep */, 30))
+  })
+
+  it('does not mutate the original date', function() {
+    const date = new Date(2014, 8 /* Sep */, 1)
+    setDate(date, 20)
+    assert.deepEqual(date, new Date(2014, 8 /* Sep */, 1))
+  })
+
+  it('returns `Invalid Date` if the given date is invalid', function() {
+    const result = setDate(new Date(NaN), 30)
+    assert(result instanceof Date && isNaN(result.getTime()))
+  })
+
+  it('returns `Invalid Date` if the given amount is NaN', function() {
+    const result = setDate(new Date(2014, 8 /* Sep */, 1), NaN)
+    assert(result instanceof Date && isNaN(result.getTime()))
+  })
+
+  it('throws TypeError exception if passed less than 2 arguments', function() {
+    assert.throws(setDate.bind(null), TypeError)
+    assert.throws(setDate.bind(null, 1), TypeError)
+  })
+})