1 files changed, 26 insertions, 0 deletions
diff --git a/date-fns/src/getDecade/test.ts b/date-fns/src/getDecade/test.ts
new file mode 100644
index 0000000..8e93bb7
--- /dev/null
+++ b/date-fns/src/getDecade/test.ts
@@ -0,0 +1,26 @@
+// @flow
+/* eslint-env mocha */
+
+import assert from 'power-assert'
+import getDecade from '.'
+
+describe('getDecade', function() {
+  it('returns the decade for a the given date', function() {
+    const result = getDecade(new Date(1971, 10 /* Nov */, 8))
+    assert(result === 1970)
+  })
+
+  it('accepts a timestamp', function() {
+    const result = getDecade(new Date(1969, 6 /* Jul */, 20).getTime())
+    assert(result === 1960)
+  })
+
+  it('returns NaN if the given date is invalid', function() {
+    const result = getDecade(new Date(NaN))
+    assert(isNaN(result))
+  })
+
+  it('throws TypeError exception if passed less than 1 argument', function() {
+    assert.throws(getDecade.bind(null), TypeError)
+  })
+})