Skip error retrying when document is not active and improve tests (vercel#1742)

* use the babel coverage reporter

* improve coverage

Author: shuding

src/use-swr.ts

@@ -77,8 +77,6 @@ export const useSWRHandler = <Data = any, Error = any>(
   const configRef = useRef(config)
   const getConfig = () => configRef.current
   const isActive = () => getConfig().isVisible() && getConfig().isOnline()
-  const patchFetchInfo = (info: { isValidating?: boolean; error?: any }) =>
-    cache.set(keyInfo, mergeObjects(cache.get(keyInfo), info))
 
   // Get the current state that SWR should return.
   const cached = cache.get(key)

test/use-swr-error.test.tsx

@@ -142,62 +142,6 @@ describe('useSWR - error', () => {
     screen.getByText('error: 0')
   })
 
-  it('should not retry when shouldRetryOnError function returns false', async () => {
-    const key = createKey()
-    let count = 0
-    function Page() {
-      const { data, error } = useSWR(
-        key,
-        () => createResponse(new Error('error: ' + count++), { delay: 100 }),
-        {
-          onErrorRetry: (_, __, ___, revalidate, revalidateOpts) => {
-            revalidate(revalidateOpts)
-          },
-          dedupingInterval: 0,
-          shouldRetryOnError: () => false
-        }
-      )
-      if (error) return <div>{error.message}</div>
-      return <div>hello, {data}</div>
-    }
-    renderWithConfig(<Page />)
-    screen.getByText('hello,')
-
-    // mount
-    await screen.findByText('error: 0')
-
-    await act(() => sleep(150))
-    screen.getByText('error: 0')
-  })
-
-  it('should retry when shouldRetryOnError function returns true', async () => {
-    const key = createKey()
-    let count = 0
-    function Page() {
-      const { data, error } = useSWR(
-        key,
-        () => createResponse(new Error('error: ' + count++), { delay: 100 }),
-        {
-          onErrorRetry: (_, __, ___, revalidate, revalidateOpts) => {
-            revalidate(revalidateOpts)
-          },
-          dedupingInterval: 0,
-          shouldRetryOnError: () => true
-        }
-      )
-      if (error) return <div>{error.message}</div>
-      return <div>hello, {data}</div>
-    }
-    renderWithConfig(<Page />)
-    screen.getByText('hello,')
-
-    // mount
-    await screen.findByText('error: 0')
-
-    await act(() => sleep(150))
-    screen.getByText('error: 1')
-  })
-
   it('should trigger the onLoadingSlow and onSuccess event', async () => {
     const key = createKey()
     let loadingSlow = null,