While testing against code that uses the boto3 logs client get_log_events() logGroupIdentifier parameter we have noticed that it always returns the following, even when a log group, log stream and events have been correctly created via Moto:
E botocore.errorfactory.ResourceNotFoundException: An error occurred (ResourceNotFoundException) when calling the GetLogEvents operation: The specified log group does not exist.

Other slight variations include the output of the describe_log_groups and describe_log_streams calls. Both below calls return an arn of the pattern arn:aws:logs:us-east-2:123456789012:log-group:test-log-group whereas looking in an actual AWS log group shows the arn pattern to differ slightly, instead being arn:aws:logs:us-east-2:123456789012:log-group:/test-log-group:* (additional forward slash after :log-group and the addition of :* at the end. When creating these in moto this is not seen. Examples:
WARNING root:tests.py:88 {'logGroups': [{'logGroupName': 'test-log-group', 'creationTime': 1733482480718, 'metricFilterCount': 0, 'arn': 'arn:aws:logs:us-east-2:123456789012:log-group:test-log-group', 'storedBytes': 0}], 'ResponseMetadata': {'RequestId': '7ptVcnqFn72o2i6w98KS7HShz7dGZHETMW6GX6m1PviCPtKA4M33', 'HTTPStatusCode': 200, 'HTTPHeaders': {'server': 'amazon.com', 'date': 'Fri, 06 Dec 2024 10:54:40 GMT', 'x-amzn-requestid': '7ptVcnqFn72o2i6w98KS7HShz7dGZHETMW6GX6m1PviCPtKA4M33'}, 'RetryAttempts': 0}}
WARNING root:tests.py:91 {'logStreams': [{'logStreamName': 'test-log-stream', 'creationTime': 1733482480719, 'arn': 'arn:aws:logs:us-east-2:123456789012:log-group:test-log-group:log-stream:test-log-stream', 'storedBytes': 0}], 'ResponseMetadata': {'RequestId': 'ByX1iiSQ0tNtxZ7iO3Nu62wDbKpvd6KMcjxqyRJMBWehsLcrQf7n', 'HTTPStatusCode': 200, 'HTTPHeaders': {'server': 'amazon.com', 'date': 'Fri, 06 Dec 2024 10:54:40 GMT', 'x-amzn-requestid': 'ByX1iiSQ0tNtxZ7iO3Nu62wDbKpvd6KMcjxqyRJMBWehsLcrQf7n'}, 'RetryAttempts': 0}}

Example code used when trying to use the logGroupIdentifier. Changing it to logGroupName as both a string and the arn does work as expected. Unfortunately the lambda code we are testing against is rather complex meaning we may not be able to easily change it:
cwlogs = boto3.client('logs') response = cwlogs.get_log_events( logGroupIdentifier=log_group_arn.rstrip(":*"), logStreamName=log_stream_name, )
Using the latest released moto version at time of writing
Cheers
Simon