広場投稿追加画面の刷新 (#399) (#413)

Reviewed-on: #413
Co-authored-by: miteruzo <miteruzo@naver.com>
Co-committed-by: miteruzo <miteruzo@naver.com>

frontend/src/components/PostOriginalCreatedTimeField.test.tsx

@@ -20,8 +20,10 @@ describe ('PostOriginalCreatedTimeField', () => {
     fireEvent.change (inputs[0], { target: { value: '2026-01-02T03:04' } })
     fireEvent.change (inputs[1], { target: { value: '2026-01-03T03:04' } })
 
-    expect (setFrom).toHaveBeenCalledWith (expect.any (String))
-    expect (setBefore).toHaveBeenCalledWith (expect.any (String))
+    expect (setFrom).toHaveBeenCalledWith (expect.stringMatching (
+	/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}Z$/))
+    expect (setBefore).toHaveBeenCalledWith (expect.stringMatching (
+	/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}Z$/))
   })
 
   it ('infers an exclusive before value on blur', () => {
@@ -38,7 +40,43 @@ describe ('PostOriginalCreatedTimeField', () => {
     const input = screen.getAllByDisplayValue ('')[0]
     fireEvent.blur (input, { target: { value: '2026-01-02T03:04' } })
 
-    expect (setBefore).toHaveBeenCalledWith (expect.any (String))
+    const value = setBefore.mock.calls.at (-1)?.[0]
+    expect (value).toMatch (/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}Z$/)
+    expect (new Date (value).getTime () - new Date ('2026-01-02T03:04').getTime ())
+	.toBe (60_000)
+  })
+
+  it ('does not rewrite mounted values that only differ by offset notation', () => {
+    const setFrom = vi.fn ()
+    const setBefore = vi.fn ()
+
+    render (
+        <PostOriginalCreatedTimeField
+            originalCreatedFrom="2024-01-01T12:34+09:00"
+            setOriginalCreatedFrom={setFrom}
+            originalCreatedBefore="2024-01-01T12:35+09:00"
+            setOriginalCreatedBefore={setBefore}/>,
+    )
+
+    expect (setFrom).not.toHaveBeenCalled ()
+    expect (setBefore).not.toHaveBeenCalled ()
+  })
+
+  it ('emits minute-precision UTC values only when the user edits the input', () => {
+    const setFrom = vi.fn ()
+
+    render (
+        <PostOriginalCreatedTimeField
+            originalCreatedFrom="2024-01-01T12:34+09:00"
+            setOriginalCreatedFrom={setFrom}
+            originalCreatedBefore={null}
+            setOriginalCreatedBefore={vi.fn ()}/>,
+    )
+
+    const input = screen.getByDisplayValue ('2024-01-01T12:34')
+    fireEvent.change (input, { target: { value: '2024-01-01T12:35' } })
+
+    expect (setFrom).toHaveBeenCalledWith ('2024-01-01T03:35Z')
   })
 
   it ('resets both values', () => {