[CI] Revise R tests. (#8430)

- Use the standard package check (check on the tarball instead of the source tree).
- Run commands in parallel.
- Cleanup dependencies installation.
- Replace makefile.
- Documentation.
- Test using the image from rhub.

tests/ci_build/test_utils.py

@@ -1,14 +1,72 @@
+"""Utilities for the CI."""
 import os
-from typing import Union
+from datetime import datetime, timedelta
+from functools import wraps
+from typing import Any, Callable, Dict, TypedDict, TypeVar, Union
 
 
 class DirectoryExcursion:
-    def __init__(self, path: Union[os.PathLike, str]):
+    def __init__(self, path: Union[os.PathLike, str]) -> None:
         self.path = path
         self.curdir = os.path.normpath(os.path.abspath(os.path.curdir))
 
-    def __enter__(self):
+    def __enter__(self) -> None:
         os.chdir(self.path)
 
-    def __exit__(self, *args):
+    def __exit__(self, *args: Any) -> None:
         os.chdir(self.curdir)
+
+
+R = TypeVar("R")
+
+
+def cd(path: Union[os.PathLike, str]) -> Callable:
+    """Decorator for changing directory temporarily."""
+
+    def chdir(func: Callable[..., R]) -> Callable[..., R]:
+        @wraps(func)
+        def inner(*args: Any, **kwargs: Any) -> R:
+            with DirectoryExcursion(path):
+                return func(*args, **kwargs)
+
+        return inner
+
+    return chdir
+
+
+Record = TypedDict("Record", {"count": int, "total": timedelta})
+timer: Dict[str, Record] = {}
+
+
+def record_time(func: Callable[..., R]) -> Callable[..., R]:
+    """Decorator for recording function runtime."""
+    global timer
+
+    @wraps(func)
+    def inner(*args: Any, **kwargs: Any) -> R:
+        if func.__name__ not in timer:
+            timer[func.__name__] = {"count": 0, "total": timedelta(0)}
+        s = datetime.now()
+        try:
+            r = func(*args, **kwargs)
+        finally:
+            e = datetime.now()
+            timer[func.__name__]["count"] += 1
+            timer[func.__name__]["total"] += e - s
+        return r
+
+    return inner
+
+
+def print_time() -> None:
+    """Print all recorded items by :py:func:`record_time`."""
+    global timer
+    for k, v in timer.items():
+        print(
+            "Name:",
+            k,
+            "Called:",
+            v["count"],
+            "Elapsed:",
+            f"{v['total'].seconds} secs",
+        )