1 files changed, 86 insertions, 0 deletions
diff --git a/date-fns/src/nextDay/test.ts b/date-fns/src/nextDay/test.ts
new file mode 100644
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--- /dev/null
+++ b/date-fns/src/nextDay/test.ts
@@ -0,0 +1,86 @@
+// @flow
+/* eslint-env mocha */
+
+import assert from 'power-assert'
+import nextDay from '.'
+
+describe('nextDay', function () {
+  it('returns the following Monday given various dates before the same', function () {
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 2 /* Mar */, 20), 1),
+      new Date(2020, 2 /* Mar */, 23)
+    )
+
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 2 /* Mar */, 19), 1),
+      new Date(2020, 2 /* Mar */, 23)
+    )
+
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 2 /* Mar */, 18), 1),
+      new Date(2020, 2 /* Mar */, 23)
+    )
+
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 2 /* Mar */, 17), 1),
+      new Date(2020, 2 /* Mar */, 23)
+    )
+
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 2 /* Mar */, 16), 1),
+      new Date(2020, 2 /* Mar */, 23)
+    )
+
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 2 /* Mar */, 22), 1),
+      new Date(2020, 2 /* Mar */, 23)
+    )
+
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 4 /* May */, 2), 1),
+      new Date(2020, 4 /* May */, 4)
+    )
+  })
+
+  it('returns the following Tuesday given the Saturday before it', function () {
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 4 /* May */, 2), 2),
+      new Date(2020, 4 /* May */, 5)
+    )
+  })
+
+  it('returns the following Wednesday given the Saturday before it', function () {
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 4 /* May */, 2), 3),
+      new Date(2020, 4 /* May */, 6)
+    )
+  })
+
+  it('returns the following Thursday given the Saturday before it', function () {
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 4 /* May */, 2), 4),
+      new Date(2020, 4 /* May */, 7)
+    )
+  })
+
+  it('returns the following Friday given the Saturday before it', function () {
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 4 /* May */, 2), 5),
+      new Date(2020, 4 /* May */, 8)
+    )
+  })
+
+  it('returns the following Saturday given the Saturday before it', function () {
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 4 /* May */, 2), 6),
+      new Date(2020, 4 /* May */, 9)
+    )
+  })
+
+  it('returns next Sunday given the day is Sunday', function () {
+    assert.deepStrictEqual(
+      nextDay(new Date(2020, 2 /* Mar */, 22), 0),
+      new Date(2020, 2 /* Mar */, 29)
+    )
+  })
+})