Added unit tests to check for BASE64 and proper handling

There is a still an error when the library is initialized with
something like `bASe64`. It is not setting it. From the code this looks
like the unintended behavior. But then I don't understand why theother test case
works when `EmBed` is given. This too should fail as per my reading of the code.
Going to trace through a bit more to see why that isn't failing and what I may be
missing.

Author: emanlove

utest/test/keywords/test_screen_shot.py

@@ -8,7 +8,7 @@
 SCREENSHOT_FILE_NAME = "selenium-screenshot-{index}.png"
 ELEMENT_FILE_NAME = "selenium-element-screenshot-{index}.png"
 EMBED = "EMBED"
-
+BASE64 = "BASE64"
 
 @pytest.fixture(scope="module")
 def screen_shot():
@@ -35,11 +35,21 @@ def test_screen_shotdir_embeded(screen_shot):
     assert screen_shot._decide_embedded("other.psn") == (False, None)
 
 
+def test_screen_shotdir_return_base64(screen_shot):
+    screen_shot.ctx.screenshot_root_directory = BASE64
+    assert screen_shot._decide_embedded(SCREENSHOT_FILE_NAME) == (True, BASE64)
+    assert screen_shot._decide_embedded(SCREENSHOT_FILE_NAME.upper()) == (True, BASE64)
+    assert screen_shot._decide_embedded(ELEMENT_FILE_NAME) == (True, BASE64)
+    assert screen_shot._decide_embedded(ELEMENT_FILE_NAME.upper()) == (True, BASE64)
+    assert screen_shot._decide_embedded("other.psn") == (False, None)
+
+
 def test_file_name_embeded(screen_shot):
-    assert screen_shot._decide_embedded(EMBED) == (True, EMBED)
     assert screen_shot._decide_embedded("other.psn") == (False, None)
     screen_shot.ctx.screenshot_root_directory = EMBED
     assert screen_shot._decide_embedded(EMBED) == (True, EMBED)
+    screen_shot.ctx.screenshot_root_directory = BASE64
+    assert screen_shot._decide_embedded(BASE64) == (True, BASE64)
 
 
 def test_screenshot_path_embedded(screen_shot):
@@ -56,6 +66,12 @@ def test_sl_init_embed():
     sl = SeleniumLibrary(screenshot_root_directory=EMBED)
     assert sl.screenshot_root_directory == EMBED
 
+    sl = SeleniumLibrary(screenshot_root_directory="bAsE64")
+    assert sl.screenshot_root_directory == BASE64
+
+    sl = SeleniumLibrary(screenshot_root_directory=BASE64)
+    assert sl.screenshot_root_directory == BASE64
+
 
 def test_sl_init_not_embed():
     sl = SeleniumLibrary(screenshot_root_directory=None)
@@ -76,6 +92,9 @@ def test_sl_set_screenshot_directory():
     sl.set_screenshot_directory(EMBED)
     assert sl.screenshot_root_directory == EMBED
 
+    sl.set_screenshot_directory(BASE64)
+    assert sl.screenshot_root_directory == BASE64
+
     sl.set_screenshot_directory("EEmBedD")
     assert "EEmBedD" in sl.screenshot_root_directory
     assert len("EEmBedD") < len(sl.screenshot_root_directory)