test: move mockWarn into setup files

scripts/setupJestEnv.ts

@@ -0,0 +1,88 @@
+expect.extend({
+  toHaveBeenWarned(received: string) {
+    asserted.add(received)
+    const passed = warn.mock.calls.some(args => args[0].indexOf(received) > -1)
+    if (passed) {
+      return {
+        pass: true,
+        message: () => `expected "${received}" not to have been warned.`
+      }
+    } else {
+      const msgs = warn.mock.calls.map(args => args[0]).join('\n - ')
+      return {
+        pass: false,
+        message: () =>
+          `expected "${received}" to have been warned.\n\nActual messages:\n\n - ${msgs}`
+      }
+    }
+  },
+
+  toHaveBeenWarnedLast(received: string) {
+    asserted.add(received)
+    const passed =
+      warn.mock.calls[warn.mock.calls.length - 1][0].indexOf(received) > -1
+    if (passed) {
+      return {
+        pass: true,
+        message: () => `expected "${received}" not to have been warned last.`
+      }
+    } else {
+      const msgs = warn.mock.calls.map(args => args[0]).join('\n - ')
+      return {
+        pass: false,
+        message: () =>
+          `expected "${received}" to have been warned last.\n\nActual messages:\n\n - ${msgs}`
+      }
+    }
+  },
+
+  toHaveBeenWarnedTimes(received: string, n: number) {
+    asserted.add(received)
+    let found = 0
+    warn.mock.calls.forEach(args => {
+      if (args[0].indexOf(received) > -1) {
+        found++
+      }
+    })
+
+    if (found === n) {
+      return {
+        pass: true,
+        message: () => `expected "${received}" to have been warned ${n} times.`
+      }
+    } else {
+      return {
+        pass: false,
+        message: () =>
+          `expected "${received}" to have been warned ${n} times but got ${found}.`
+      }
+    }
+  }
+})
+
+let warn: jest.SpyInstance
+const asserted: Set<string> = new Set()
+
+beforeEach(() => {
+  asserted.clear()
+  warn = jest.spyOn(console, 'warn')
+  warn.mockImplementation(() => {})
+})
+
+afterEach(() => {
+  const assertedArray = Array.from(asserted)
+  const nonAssertedWarnings = warn.mock.calls
+    .map(args => args[0])
+    .filter(received => {
+      return !assertedArray.some(assertedMsg => {
+        return received.indexOf(assertedMsg) > -1
+      })
+    })
+  warn.mockRestore()
+  if (nonAssertedWarnings.length) {
+    nonAssertedWarnings.forEach(warning => {
+      console.warn(warning)
+    })
+    throw new Error(`test case threw unexpected warnings.`)
+  }
+})