Fix up autest - Should fix autest on 9.0.x

CHANGELOG-9.0.0

@@ -1013,7 +1013,7 @@ Changes with Apache Traffic Server 9.0.0
   #7004 - Fixed core when sending back a redirect and having an invalid server response
   #7005 - Added tasks and launch files for vscode, to configure, build and debug
   #7007 - Updates to thread scale factor
-  #7008 - slice plugin: fix throttle not work 
+  #7008 - slice plugin: fix throttle not work
   #7012 - Remove incorrect assert in inactivity timeout handling
   #7031 - Fix code to eliminate warning and enable feature
   #7035 - Add a null check to avoid crashing

tests/gold_tests/autest-site/when.test.ext

@@ -19,18 +19,67 @@ When extensions.
 
 from autest.api import AddWhenFunction
 import hosts.output as host
+import os
+import re
 
 
-def FileContains(haystack, needle):
+def FileContains(haystack, needle, desired_count=1):
+    """
+    Return whether the file haystack contains the string needle.
+
+    Args:
+        haystack (str): The path to the file to be inspected.
+        needle (str): The content to look for in haystack. This can be a
+            regular expression which will be used in Python's re.search
+            function.
+        desired_count (int): How many times the caller desires to see needle in
+            haystack before considering the When condition fulfilled.
+
+    Returns:
+        True if the haystack exists as a file and contains needle, False
+        otherwise.
+    """
+
+    if desired_count < 0:
+        raise ValueError("Cannot pass a negative desired_count value to FileContains.")
+    if desired_count == 0:
+        raise ValueError("Cannot pass a desired_count of 0 to FileContains.")
+
+    if not os.path.exists(haystack):
+        host.WriteDebug(
+            ['FileContains', 'when'],
+            "Testing for file content '{0}' in file '{1}': file does not exist".format(
+                needle, haystack))
+        return False
+
+    needle_regex = re.compile(needle)
     with open(haystack) as f:
-        result = needle in f.read()
+        needle_seen_count = 0
+        line_count = 0
+        for line in f:
+            line_count += 1
+            if needle_regex.search(line):
+                host.WriteDebug(
+                    ['FileContains', 'when'],
+                    "Found '{0}' in file '{1}' in line: '{2}', line number: {3}".format(
+                        needle, haystack, line.rstrip(), line_count))
+                needle_seen_count += 1
+
+                if needle_seen_count >= desired_count:
+                    host.WriteDebug(
+                        ['FileContains', 'when'],
+                        "Testing for file content '{0}' in file '{1}', "
+                        "successfully found it the desired {2} times".format(
+                            needle, haystack, needle_seen_count))
+                    return True
 
         host.WriteDebug(
-            ['FileExists', 'when'],
-            "Testing for file content '{0}' in '{1}' : {2}".format(
-                needle, haystack, result))
+            ['FileContains', 'when'],
+            "Testing for file content '{0}' in file '{1}', only seen {2} "
+            "out of the desired {3} times".format(
+                needle, haystack, needle_seen_count, desired_count))
 
-        return result
+        return False
 
 
 AddWhenFunction(FileContains)