igloo: pin the requested graph window and the no-data state

useGraphData passes start and end through verbatim, so a window
reaching past the retained data is never silently narrowed.

A window that returns no data does state something, but names the
wrong cause: it reuses the hidden-metrics message. Pinned as-is so
the wording and its test change together.

JIRA-Ref: CMK-37024
Change-Id: Ia919746d9e9e891abb3054c6afaa23308e7c991c

Author: smeagol91

packages/cmk-frontend-vue/tests/graphing/components/GraphPanel.test.ts

@@ -657,3 +657,18 @@ test('keeps the all-hidden message when data arrived but nothing is shown', () =
   expect(screen.getByText('All metrics are hidden')).toBeInTheDocument()
   expect(screen.getByTestId('time-series-graph')).toBeInTheDocument()
 })
+
+test('a window that returned no data reuses the all-hidden message', () => {
+  render(GraphPanel, {
+    props: {
+      metrics: [],
+      dataTimeRange: TIME_RANGE,
+      requestedTimeRange: REQUESTED,
+      interaction: INTERACTION_NONE
+    }
+  })
+
+  // Pins today's wording: nothing was hidden, there was nothing to show. Change both together.
+  expect(screen.getByText('All metrics are hidden')).toBeInTheDocument()
+  expect(screen.getByTestId('time-series-graph')).toBeInTheDocument()
+})

packages/cmk-frontend-vue/tests/graphing/composables/useGraphData.test.ts

@@ -128,6 +128,17 @@ describe('useGraphData — requested resolution', () => {
     const samplesPerColumn = (eightDays.end - eightDays.start) / step / columns
     expect(samplesPerColumn).toBeCloseTo(4, 1)
   })
+
+  test('a window reaching past the retained data is asked for verbatim', async () => {
+    // Narrowing here would redraw a different period than the picker states, so only the step
+    // is ever derived.
+    const fourHundredDays = { start: 0, end: 400 * 86_400 }
+
+    fetchFor(fourHundredDays, 750)
+
+    const { start, end } = await requestedTimeRange()
+    expect({ start, end }).toEqual(fourHundredDays)
+  })
 })
 
 /** Mounts the composable on the given fetcher and hands back the diagnostics it exposes. */