[VOQ][saidump] Add saidump unit test scripts #3079

#2972 added two below functions into scripts/generate_dump.
get_route_table_size_by_asic_id_and_ipver
save_saidump_by_route_size
The unittest scripts need to be added.

Related PRs:
#2972
sonic-net/sonic-buildimage#16466
sonic-net/sonic-sairedis#1288
sonic-net/sonic-sairedis#1298

Microsoft ADO (25892277):

Add two scripts:
tests/saidump_test.py
tests/saidump_test.sh

To use below 6 test cases to verify the functionality of get_route_table_size_by_asic_id_and_ipver and save_saidump_by_route_size behave correctly.

```
saidump test list format: [ACIS number, ipv4 and ipv6 route table size, expected function save_cmd arguments]
saidump_test_list = [
    [1, 10000, "docker exec syncd saidump saidump"],
    [1, 12000, "docker exec syncd saidump saidump"],
    [1, 12001, "docker exec syncd saidump.sh saidump"],
    [1, 20000, "docker exec syncd saidump.sh saidump"],
    [2, 10000, "docker exec syncd0 saidump saidump0\ndocker exec syncd1 saidump saidump1"],
    [2, 12000, "docker exec syncd0 saidump saidump0\ndocker exec syncd1 saidump saidump1"],
    [2, 12001, "docker exec syncd0 saidump.sh saidump0\ndocker exec syncd1 saidump.sh saidump1"],
    [2, 20000, "docker exec syncd0 saidump.sh saidump0\ndocker exec syncd1 saidump.sh saidump1"]
]
```
During the compiling stage, run the below command to check if it's PASSED.
jumao@1b1ffba5949a:/sonic/src/sonic-utilities$ time python3 setup.py test
tests/saidump_test.py::test_saidump PASSED

tests/saidump_test.py

@@ -0,0 +1,56 @@
+import os
+import subprocess
+
+GENERATE_DUMP_FILE = "/tmp/generate_dump_tmp"
+
+test_path = os.path.dirname(os.path.abspath(__file__))
+modules_path = os.path.dirname(test_path)
+scripts_path = os.path.join(modules_path, "scripts")
+
+
+def run_saidump(asic_num, route_num):
+    result = subprocess.run([". " + test_path + "/saidump_test.sh && test_saidump " + str(asic_num) +
+                            " " + str(route_num)], capture_output=True, text=True, shell=True, executable='/bin/bash')
+    return result.stdout.strip()
+
+
+# saidump test list format: [ACIS number, ipv4 and ipv6 route table size, expected function save_cmd arguments]
+saidump_test_list = [
+    [1, 10000, "docker exec syncd saidump saidump"],
+    [1, 12000, "docker exec syncd saidump saidump"],
+    [1, 12001, "docker exec syncd saidump.sh saidump"],
+    [1, 20000, "docker exec syncd saidump.sh saidump"],
+    [2, 10000, "docker exec syncd0 saidump saidump0\ndocker exec syncd1 saidump saidump1"],
+    [2, 12000, "docker exec syncd0 saidump saidump0\ndocker exec syncd1 saidump saidump1"],
+    [2, 12001, "docker exec syncd0 saidump.sh saidump0\ndocker exec syncd1 saidump.sh saidump1"],
+    [2, 20000, "docker exec syncd0 saidump.sh saidump0\ndocker exec syncd1 saidump.sh saidump1"]
+]
+
+
+def shell_pre_process(in_file, out_file):
+    buf = []
+
+    with open(in_file, 'r') as file:
+        lines = file.readlines()
+
+    for line in lines:
+        if line.strip().startswith("while getopts"):
+            break
+        else:
+            buf.append(line)
+
+    # Write the modified content back to the file
+    with open(out_file, 'w') as file:
+        file.writelines(buf)
+
+
+def test_saidump():
+    # preprocess the generate_dump to a new script without non-functional codes
+    shell_pre_process(scripts_path + '/generate_dump', GENERATE_DUMP_FILE)
+
+    for item in saidump_test_list:
+        output = run_saidump(item[0], item[1])
+        assert output == item[2]
+
+    if os.path.exists(GENERATE_DUMP_FILE):
+        os.remove(GENERATE_DUMP_FILE)

tests/saidump_test.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+GENERATE_DUMP_FILE="/tmp/generate_dump_tmp"
+ROUTE_FILE="/tmp/route_summary.txt"
+shopt -s expand_aliases
+alias eval="mock_eval"
+alias save_cmd="mock_save_cmd"
+
+source $GENERATE_DUMP_FILE
+
+mock_route_summary(){
+    local routenum=$1
+    echo "\
+    {
+    \"routesTotal\":$routenum
+    }" > $ROUTE_FILE
+}
+
+route_num=0
+save_cmd_arguments=""
+
+# Mock eval command in function get_route_table_size_by_asic_id_and_ipver
+mock_eval(){
+    mock_route_summary $route_num
+}
+
+# Mock function save_cmd called in function save_saidump_by_route_size
+mock_save_cmd(){    
+    save_cmd_arguments="$save_cmd_arguments$*\n"
+}
+
+test_saidump(){
+    NUM_ASICS=$1
+    route_num=$2
+    save_saidump_by_route_size > /dev/null
+    echo -e $save_cmd_arguments
+    local ret=$save_cmd_arguments
+    save_cmd_arguments=""
+    rm $ROUTE_FILE
+    return $ret    
+}