diff --git a/src/rpcclient/rpcclient/darwin/consts.py b/src/rpcclient/rpcclient/darwin/consts.py
index f61c1b45..a07600c3 100644
--- a/src/rpcclient/rpcclient/darwin/consts.py
+++ b/src/rpcclient/rpcclient/darwin/consts.py
@@ -58,3 +58,32 @@ class CFStringEncoding(Enum):
     kCFStringEncodingUTF32 = 0x0c000100  # kTextEncodingUnicodeDefault + kUnicodeUTF32Format
     kCFStringEncodingUTF32BE = 0x18000100  # kTextEncodingUnicodeDefault + kUnicodeUTF32BEFormat
     kCFStringEncodingUTF32LE = 0x1c000100  # kTextEncodingUnicodeDefault + kUnicodeUTF32LEFormat
+
+
+class NSStringEncoding(Enum):
+    NSASCIIStringEncoding = 1  # 0..127 only
+    NSNEXTSTEPStringEncoding = 2
+    NSJapaneseEUCStringEncoding = 3
+    NSUTF8StringEncoding = 4
+    NSISOLatin1StringEncoding = 5
+    NSSymbolStringEncoding = 6
+    NSNonLossyASCIIStringEncoding = 7
+    NSShiftJISStringEncoding = 8  # kCFStringEncodingDOSJapanese
+    NSISOLatin2StringEncoding = 9
+    NSUnicodeStringEncoding = 10
+    NSWindowsCP1251StringEncoding = 11  # Cyrillic; same as AdobeStandardCyrillic
+    NSWindowsCP1252StringEncoding = 12  # WinLatin1
+    NSWindowsCP1253StringEncoding = 13  # Greek
+    NSWindowsCP1254StringEncoding = 14  # Turkish
+    NSWindowsCP1250StringEncoding = 15  # WinLatin2
+    NSISO2022JPStringEncoding = 21  # ISO 2022 Japanese encoding for e-mail
+    NSMacOSRomanStringEncoding = 30
+
+    NSUTF16StringEncoding = NSUnicodeStringEncoding  # An alias for NSUnicodeStringEncoding
+
+    NSUTF16BigEndianStringEncoding = 0x90000100  # NSUTF16StringEncoding encoding with explicit endianness specified
+    NSUTF16LittleEndianStringEncoding = 0x94000100  # NSUTF16StringEncoding encoding with explicit endianness specified
+
+    NSUTF32StringEncoding = 0x8c000100
+    NSUTF32BigEndianStringEncoding = 0x98000100  # NSUTF32StringEncoding encoding with explicit endianness specified
+    NSUTF32LittleEndianStringEncoding = 0x9c000100  # NSUTF32StringEncoding encoding with explicit endianness specified
diff --git a/src/rpcclient/tests/conftest.py b/src/rpcclient/tests/conftest.py
index 94932181..006931b6 100644
--- a/src/rpcclient/tests/conftest.py
+++ b/src/rpcclient/tests/conftest.py
@@ -1,15 +1,14 @@
+from contextlib import closing
+
 import pytest
 
-from rpcclient.client_factory import create_client
+from rpcclient.client_factory import create_client, DarwinClient
 
 
 @pytest.fixture
 def client():
-    try:
-        c = create_client('127.0.0.1')
+    with closing(create_client('127.0.0.1')) as c:
         yield c
-    finally:
-        c.close()
 
 
 def pytest_addoption(parser):
@@ -21,13 +20,20 @@ def pytest_configure(config):
         'markers',
         '''local_only: marks tests that require features the CI lacks (deselect with '-m "not local_only"')'''
     )
+    config.addinivalue_line('markers', 'darwin: marks tests that require darwin platform to run')
 
 
 def pytest_collection_modifyitems(config, items):
-    if not config.getoption('--ci'):
-        # --ci given in cli: skip local only tests.
-        return
     skip_local_only = pytest.mark.skip(reason='remove --ci option to run')
+    skip_not_darwin = pytest.mark.skip(reason='Darwin system is required for this test')
+
+    with closing(create_client('127.0.0.1')) as c:
+        is_darwin = isinstance(c, DarwinClient)
+
     for item in items:
-        if 'local_only' in item.keywords:
+        if 'local_only' in item.keywords and config.getoption('--ci'):
+            # --ci given in cli: skip local only tests.
             item.add_marker(skip_local_only)
+        if 'darwin' in item.keywords and not is_darwin:
+            # Skip test that require Darwin on non Darwin system
+            item.add_marker(skip_not_darwin)
diff --git a/src/rpcclient/tests/test_objc.py b/src/rpcclient/tests/test_objc.py
deleted file mode 100644
index bbea5745..00000000
--- a/src/rpcclient/tests/test_objc.py
+++ /dev/null
@@ -1,8 +0,0 @@
-def test_objc(client):
-    d = client.symbols.objc_getClass('NSMutableDictionary').objc_call('new').objc_symbol
-
-    # call method
-    d.setObject_forKey_(client.cf('value'), client.cf('key'))
-
-    # call property
-    assert '{\n    key = value;\n}' == d.description.py
diff --git a/src/rpcclient/tests/test_objc_symbol.py b/src/rpcclient/tests/test_objc_symbol.py
new file mode 100644
index 00000000..87a36d50
--- /dev/null
+++ b/src/rpcclient/tests/test_objc_symbol.py
@@ -0,0 +1,23 @@
+import pytest
+
+from rpcclient.darwin.consts import NSStringEncoding
+
+
+@pytest.mark.darwin
+def test_method_by_method_name(client):
+    NSString = client.objc_get_class('NSString')
+    ascii_encoding = NSStringEncoding.NSASCIIStringEncoding
+    str1 = NSString.stringWithCString_encoding_('Taylor Swift', ascii_encoding).objc_symbol
+    assert str1.cStringUsingEncoding_(ascii_encoding).peek_str() == 'Taylor Swift'
+    assert str1.length == len('Taylor Swift')
+    assert str1.lowercaseString().cStringUsingEncoding_(ascii_encoding).peek_str() == 'taylor swift'
+    assert str1.uppercaseString().cStringUsingEncoding_(ascii_encoding).peek_str() == 'TAYLOR SWIFT'
+
+
+@pytest.mark.darwin
+def test_calling_property(client):
+    d = client.symbols.objc_getClass('NSMutableDictionary').objc_call('new').objc_symbol
+    # call method
+    d.setObject_forKey_(client.cf('value'), client.cf('key'))
+    # call property
+    assert '{\n    key = value;\n}' == d.description.py