diff --git a/atest/acceptance/1-plugin/plugin_does_not_exist.robot b/atest/acceptance/1-plugin/plugin_does_not_exist.robot
index 503c32f71..e97d25f21 100644
--- a/atest/acceptance/1-plugin/plugin_does_not_exist.robot
+++ b/atest/acceptance/1-plugin/plugin_does_not_exist.robot
@@ -1,5 +1,5 @@
 *** Variables ***
-${SERVER}=         localhost:7000
+${SERVER}=         localhost:${PORT}
 ${BROWSER}=        firefox
 ${REMOTE_URL}=     ${NONE}
 ${ROOT}=           http://${SERVER}/html
diff --git a/atest/acceptance/1-plugin/plugin_open_browser.robot b/atest/acceptance/1-plugin/plugin_open_browser.robot
index 41247443b..9d391d956 100644
--- a/atest/acceptance/1-plugin/plugin_open_browser.robot
+++ b/atest/acceptance/1-plugin/plugin_open_browser.robot
@@ -2,7 +2,7 @@
 Library    SeleniumLibrary    plugins=${CURDIR}/OpenBrowserExample.py
 
 *** Variables ***
-${SERVER}=         localhost:7000
+${SERVER}=         localhost:${PORT}
 ${ROOT}=           http://${SERVER}/html
 &{EXTRA DICTIONARY}    extra=dictionary    key=value
 
diff --git a/atest/acceptance/2-event_firing_webdriver/event_firing_webdriver.robot b/atest/acceptance/2-event_firing_webdriver/event_firing_webdriver.robot
index b31c8fa91..2ee7904a1 100644
--- a/atest/acceptance/2-event_firing_webdriver/event_firing_webdriver.robot
+++ b/atest/acceptance/2-event_firing_webdriver/event_firing_webdriver.robot
@@ -1,7 +1,7 @@
 *** Settings ***
 Library           SeleniumLibrary    event_firing_webdriver=${CURDIR}/../../resources/testlibs/MyListener.py
 Resource          resource_event_firing_webdriver.robot
-Suite Setup       Open Browser    ${FRONT PAGE}    ${BROWSER}    alias=event_firing_webdriver
+Suite Setup       Open Browser    ${FRONT_PAGE}    ${BROWSER}    alias=event_firing_webdriver
 ...                   remote_url=${REMOTE_URL}
 Suite Teardown    Close All Browsers
 
@@ -14,7 +14,7 @@ Open Browser To Start Page
     [Documentation]
     ...    LOG 1:31 DEBUG  Wrapping driver to event_firing_webdriver.
     ...    LOG 1:33 INFO  Got driver also from SeleniumLibrary.
-    Open Browser    ${FRONT PAGE}    ${BROWSER}    remote_url=${REMOTE_URL}
+    Open Browser    ${FRONT_PAGE}    ${BROWSER}    remote_url=${REMOTE_URL}
 
 Event Firing Webdriver Go To (WebDriver)
     [Tags]    NoGrid
diff --git a/atest/acceptance/2-event_firing_webdriver/resource_event_firing_webdriver.robot b/atest/acceptance/2-event_firing_webdriver/resource_event_firing_webdriver.robot
index a224bc9bd..27e92aab7 100644
--- a/atest/acceptance/2-event_firing_webdriver/resource_event_firing_webdriver.robot
+++ b/atest/acceptance/2-event_firing_webdriver/resource_event_firing_webdriver.robot
@@ -1,14 +1,7 @@
-*** Variables ***
-${SERVER}=                  localhost:7000
-${BROWSER}=                 Chrome
-${REMOTE_URL}=              ${NONE}
-${DESIRED_CAPABILITIES}=    ${NONE}
-${ROOT}=                    http://${SERVER}/html
-${FRONT_PAGE}=              ${ROOT}/
+*** Settings ***
+Resource    ../variables.robot
 
 *** Keywords ***
-
 Go To Page "${relative url}"
     [Documentation]    Goes to page
     Go To    ${ROOT}/${relative url}
-
diff --git a/atest/acceptance/keywords/click_element_modifier.robot b/atest/acceptance/keywords/click_element_modifier.robot
index f83a0317d..f3b9ac5ce 100644
--- a/atest/acceptance/keywords/click_element_modifier.robot
+++ b/atest/acceptance/keywords/click_element_modifier.robot
@@ -5,19 +5,23 @@ Resource          ../resource.robot
 
 *** Test Cases ***
 Click Element Modifier CTRL
+    [Tags]   SKIP_ON_MAC
     Click Element    Button    modifier=CTRL
     Element Text Should Be    output    CTRL click
 
 Click Link Modifier CTRL
+    [Tags]   SKIP_ON_MAC
     Click Link    link text    modifier=CTRL
     Element Text Should Be    output    CTRL click
     [Teardown]    Close Popup Window
 
 Click Button Modifier CTRL
+    [Tags]   SKIP_ON_MAC
     Click Button    Click me!    modifier=CTRL
     Element Text Should Be    output    CTRL click
 
 Click Image Modifier CTRL
+    [Tags]   SKIP_ON_MAC
     Click Image    robot    modifier=CTRL
     Element Text Should Be    output    CTRL click
 
@@ -46,7 +50,7 @@ Click Element Action Chain and modifier
     [Documentation]     LOG 1:1 INFO Clicking element 'Button' with CTRL.
     Click Element    Button    modifier=CTRL    action_chain=True
     Element Text Should Be    output    CTRL click
-    
+
 *** Keywords ***
 Initialize Page
     Reload Page
diff --git a/atest/acceptance/keywords/elements.robot b/atest/acceptance/keywords/elements.robot
index fa053b0ff..a93ccd219 100644
--- a/atest/acceptance/keywords/elements.robot
+++ b/atest/acceptance/keywords/elements.robot
@@ -90,7 +90,7 @@ Get DOM Attribute
     Should Be Equal    ${id}    some_id
     # Test custom attribute
     ${existing_custom_attr}=   Get DOM Attribute    id:emptyDiv  data-id
-    Should Be Equal    ${existing_custom_attr}    my_id    
+    Should Be Equal    ${existing_custom_attr}    my_id
     ${doesnotexist_custom_attr}=   Get DOM Attribute    id:emptyDiv  data-doesnotexist
     Should Be Equal    ${doesnotexist_custom_attr}    ${None}
     # Get non existing DOM Attribute
@@ -156,7 +156,7 @@ Get Element Attribute And Element Attribute Value Should Be Should have same res
     Element Attribute Value Should Be  css=#second_div  class  ${attribute_value}
 
 Get Element Attribute Value Should Be Should Be Succesfull with non-ascii characters
-    Element Attribute Value Should Be  link=Link with Unicode äöüÄÖÜß  href  http://localhost:7000/html/index.html
+    Element Attribute Value Should Be  link=Link with Unicode äöüÄÖÜß  href  ${FRONT_PAGE}index.html
 
 Get Element Attribute Value Should Be Should Be Succesfull error and error messages
     Run Keyword And Expect Error
@@ -169,8 +169,8 @@ Get Element Attribute Value Should Be Should Be Succesfull error and error messa
     ...    Element with locator 'id=non_existing' not found.
     ...    Element Attribute Value Should Be  id=non_existing  href  http://non_existing.com
     Run Keyword And Expect Error
-    ...    Element 'link=Target opens in new window' attribute should have value 'http://localhost:7000/html/indéx.html' (str) but its value was 'http://localhost:7000/html/index.html' (str).
-    ...    Element Attribute Value Should Be  link=Target opens in new window  href  http://localhost:7000/html/indéx.html
+    ...    Element 'link=Target opens in new window' attribute should have value '${FRONT_PAGE}indéx.html' (str) but its value was '${FRONT_PAGE}index.html' (str).
+    ...    Element Attribute Value Should Be  link=Target opens in new window  href  ${FRONT_PAGE}indéx.html
 
 Get Horizontal Position
     ${pos}=    Get Horizontal Position    link=Link
diff --git a/atest/acceptance/keywords/location.robot b/atest/acceptance/keywords/location.robot
index 19d9ac1d8..d96fdb3aa 100644
--- a/atest/acceptance/keywords/location.robot
+++ b/atest/acceptance/keywords/location.robot
@@ -44,12 +44,13 @@ Wait Until Location Contains At The End
 Wait Until Location Contains In The Middle
     [Setup]    Go To Page "javascript/wait_location.html"
     Click Element   button
-    Wait Until Location Contains     7000
+    Wait Until Location Contains     ${PORT}
 
 Wait Until Location Contains As Number
     [Setup]    Go To Page "javascript/wait_location.html"
     Click Element   button
-    Wait Until Location Contains     ${7000}
+    ${number}    Convert To Integer    ${PORT}
+    Wait Until Location Contains     ${number}
 
 Wait Until Location Contains Fails
     [Setup]    Go To Page "javascript/wait_location.html"
@@ -70,7 +71,7 @@ Wait Until Location Contains Fails With Timeout
 Wait Until Location Is
     [Setup]    Go To Page "javascript/wait_location.html"
     Click Element   button
-    Wait Until Location Is     http://localhost:7000/html/
+    Wait Until Location Is     ${FRONT_PAGE}
 
 Wait Until Location Is Fails
     [Setup]    Go To Page "javascript/wait_location.html"
@@ -91,14 +92,14 @@ Wait Until Location Is Fails With Timeout
 Wait Until Location Is Not
     [Setup]    Go To Page "javascript/wait_location.html"
     Click Element   button
-    Wait Until Location Is Not     http://localhost:7000/html/javascript/wait_location.html
+    Wait Until Location Is Not     ${FRONT_PAGE}javascript/wait_location.html
 
 Wait Until Location Is Not Fail
     [Setup]    Go To Page "javascript/wait_location.html"
     ${orig_timeout}=    Set Selenium Timeout    2 s
     Run Keyword And Expect Error
-    ...     Location is 'http://localhost:7000/html/javascript/wait_location.html' in 2 seconds.
-    ...     Wait Until Location Is Not  http://localhost:7000/html/javascript/wait_location.html
+    ...     Location is '${FRONT_PAGE}javascript/wait_location.html' in 2 seconds.
+    ...     Wait Until Location Is Not  ${FRONT_PAGE}javascript/wait_location.html
     Set Selenium Timeout    ${orig_timeout}
 
 Wait Until Location Is Not Fails With Timeout
@@ -106,8 +107,8 @@ Wait Until Location Is Not Fails With Timeout
     ${orig_timeout}=    Set Selenium Timeout    2 s
     Click Element   button
     Run Keyword And Expect Error
-    ...     Location is 'http://localhost:7000/html/javascript/wait_location.html' in 750 milliseconds.
-    ...     Wait Until Location Is Not     http://localhost:7000/html/javascript/wait_location.html   timeout=750ms
+    ...     Location is '${FRONT_PAGE}javascript/wait_location.html' in 750 milliseconds.
+    ...     Wait Until Location Is Not     ${FRONT_PAGE}javascript/wait_location.html   timeout=750ms
     Set Selenium Timeout    ${orig_timeout}
 
 Wait Until Location Is Not Fails With Message
@@ -116,7 +117,7 @@ Wait Until Location Is Not Fails With Message
     ${orig_timeout}=    Set Selenium Timeout    2 s
     Run Keyword And Expect Error
     ...     my_message
-    ...     Wait Until Location Is Not     http://localhost:7000/html/javascript/wait_location.html  message=my_message
+    ...     Wait Until Location Is Not     ${FRONT_PAGE}javascript/wait_location.html  message=my_message
     Set Selenium Timeout    ${orig_timeout}
 
 Wait Until Location Does Not Contain
@@ -143,9 +144,10 @@ Wait Until Location Does Not Contain Fail In The Middle
 Wait Until Location Does Not Contain Fail As Number
     [Setup]    Go To Page "javascript/wait_location.html"
     ${orig_timeout}=    Set Selenium Timeout    2 s
+    ${number}    Convert To Integer    ${PORT}
     run keyword and expect error
-    ...    Location did contain '${7000}' in 2 seconds.
-    ...    Wait Until Location Does Not Contain   ${7000}
+    ...    Location did contain '${number}' in 2 seconds.
+    ...    Wait Until Location Does Not Contain   ${number}
     Set Selenium Timeout    ${orig_timeout}
 
 Wait Until Location Does Not Contain Fail At The End
diff --git a/atest/acceptance/resource.robot b/atest/acceptance/resource.robot
index 4bcaf38eb..7b429d0ff 100644
--- a/atest/acceptance/resource.robot
+++ b/atest/acceptance/resource.robot
@@ -3,15 +3,7 @@ Library           SeleniumLibrary    run_on_failure=Nothing    implicit_wait=0.2
 Library           Collections
 Library           OperatingSystem
 Library           DateTime
-
-*** Variables ***
-${SERVER}=         localhost:7000
-${BROWSER}=        firefox
-${REMOTE_URL}=     ${NONE}
-${DESIRED_CAPABILITIES}=    ${NONE}
-${ROOT}=           http://${SERVER}/html
-${FRONT_PAGE}=     ${ROOT}/
-${SPEED}=          0
+Resource          variables.robot
 
 *** Keywords ***
 Open Browser To Start Page
diff --git a/atest/acceptance/variables.robot b/atest/acceptance/variables.robot
new file mode 100644
index 000000000..b613ccb5a
--- /dev/null
+++ b/atest/acceptance/variables.robot
@@ -0,0 +1,9 @@
+*** Variables ***
+${PORT}=           7000
+${SERVER}=         localhost:${PORT}
+${BROWSER}=        firefox
+${REMOTE_URL}=     ${NONE}
+${DESIRED_CAPABILITIES}=    ${NONE}
+${ROOT}=           http://${SERVER}/html
+${FRONT_PAGE}=     ${ROOT}/
+${SPEED}=          0
\ No newline at end of file
diff --git a/atest/resources/html/javascript/wait_location.html b/atest/resources/html/javascript/wait_location.html
index c4e96c147..68bc0478e 100644
--- a/atest/resources/html/javascript/wait_location.html
+++ b/atest/resources/html/javascript/wait_location.html
@@ -5,7 +5,8 @@
         setTimeout('doLocation()', 1000)
     }
     function doLocation() {
-        self.location = 'http://localhost:7000/html/'
+        var base_url = window.location.origin;
+        self.location = `${base_url}/html/`
     }
 </script>
 <head>
diff --git a/atest/resources/testserver/testserver.py b/atest/resources/testserver/testserver.py
index 565c6506f..b3e582e88 100644
--- a/atest/resources/testserver/testserver.py
+++ b/atest/resources/testserver/testserver.py
@@ -1,6 +1,7 @@
 # Initially based on:
 # http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/336012
 
+import argparse
 import os
 import sys
 
@@ -40,11 +41,14 @@ def start_server(path, port=7000):
 
 
 if __name__ == "__main__":
-    if len(sys.argv) != 2 or sys.argv[1] not in ["start", "stop"]:
-        print("usage: %s start|stop" % sys.argv[0])
-        sys.exit(1)
-    if sys.argv[1] == "start":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("command", choices=["start", "stop"])
+    parser.add_argument("--port", default=7000, type=int)
+    args = parser.parse_args()
+    port = args.port
+    command = args.command
+    if command == "start":
         path = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-        start_server(path)
+        start_server(path, port)
     else:
-        stop_server()
+        stop_server(port)
diff --git a/atest/run.py b/atest/run.py
index 2c86cf994..3e7960a15 100755
--- a/atest/run.py
+++ b/atest/run.py
@@ -53,6 +53,7 @@
 from robot import rebot_cli
 from robot import __version__ as robot_version
 from selenium import __version__ as selenium_version
+from selenium.webdriver.common.utils import free_port
 from robot.utils import is_truthy
 
 try:
@@ -107,10 +108,12 @@ def acceptance_tests(
     if os.path.exists(RESULTS_DIR):
         shutil.rmtree(RESULTS_DIR)
     os.mkdir(RESULTS_DIR)
+    port = free_port()
+    print(f"Using port: {port}")
     if grid:
         hub, node = start_grid()
-    with http_server(interpreter):
-        execute_tests(interpreter, browser, rf_options, grid, event_firing)
+    with http_server(interpreter, port):
+        execute_tests(interpreter, browser, rf_options, grid, event_firing, port)
     failures = process_output(browser)
     if failures:
         print(
@@ -178,23 +181,23 @@ def _grid_status(status=False, role="hub"):
 
 
 @contextmanager
-def http_server(interpreter):
+def http_server(interpreter, port:int):
     serverlog = open(os.path.join(RESULTS_DIR, "serverlog.txt"), "w")
     interpreter = "python" if not interpreter else interpreter
     process = subprocess.Popen(
-        [interpreter, HTTP_SERVER_FILE, "start"],
+        [interpreter, HTTP_SERVER_FILE, "start", "--port", str(port)],
         stdout=serverlog,
         stderr=subprocess.STDOUT,
     )
     try:
         yield
     finally:
-        subprocess.call([interpreter, HTTP_SERVER_FILE, "stop"])
+        subprocess.call([interpreter, HTTP_SERVER_FILE, "stop", "--port", str(port)])
         process.wait()
         serverlog.close()
 
 
-def execute_tests(interpreter, browser, rf_options, grid, event_firing):
+def execute_tests(interpreter, browser, rf_options, grid, event_firing, port):
     options = []
     if grid:
         runner = interpreter.split() + [
@@ -204,7 +207,11 @@ def execute_tests(interpreter, browser, rf_options, grid, event_firing):
             "2",
         ]
     else:
-        runner = interpreter.split() + ["-m", "robot.run"]
+        runner = interpreter.split() + ["-m", "robot.run", "--variable", f"PORT:{port}"]
+    if platform.system() == "Darwin":
+        runner.append("--exclude")
+        runner.append("SKIP_ON_MAC")
+
     options.extend([opt.format(browser=browser) for opt in ROBOT_OPTIONS])
     if rf_options:
         options += rf_options