Split integration tests(IT) and unit tests(UT) in TiDB repo

[Defined2014]

Goals:

• Migrate IT (Integration Test) from *_test.go to tests/integrationtest
• Replace the existing testing tool in tidb/blob/master/cmd/explaintest/main.go with mysql-tester
  • Related PR: explaintest: use mysql-tester in explaintest #45995
• Utilize mysql-tester for native concurrency support, eliminating the need for scripts or CI pipeline control
• Provide coverage reporting for explaintest
  • Related PRs: #45930, #2342
• tests: update run-tests.sh for integrationtest #49160
• (optional) Add linter to disable adding IT in *test.go.
• (optional) Support for Bazel cache

Current Status of cmd/explaintest:

• check_dev: Runs tidb + unistore (use 34s, 08/23)
• check_dev2: Runs tidb + tikv (use 39s, 08/23)

Optional:

• Migrate tests to planner/core/casetest directory
  • Pros
    • Inherent support for concurrency and Bazel cache
  • Cons
    • Currently doesn't support running with tikv
    • Coverage statistics would include in UT (Unit Tests), making later analysis less convenient

Sub Tasks

• Move IT in autoid_service/ to explaintest, files number 1
• Move IT in bindinfo/ to tests/integrationtest, files number 7 #47124
• (SKIP) Move IT in br/ to explaintest, files number 147, only 5 cases related CreateMockStore, skip it now.
• Move IT in config/ to explaintest, files number 2
• Move IT in ddl/ to explaintest, files number 80 #47429
• Move IT in distsql/ to explaintest, files number 4
• Move IT in disttask/ to explaintest, files number 8
• Move IT in domain/ to explaintest, files number 13
• Move IT in dumpling/ to explaintest, files number 15
• Move IT in errno/ to explaintest, files number 1
• Move IT in executor/ to tests/integrationtest #47076
• Move IT in expression/ to explaintest, files number 65 #46679
• Move IT in extension/ to explaintest, files number 4
• Move IT in infoschema/ to explaintest, files number 6 #47237
• Move IT in keyspace/ to explaintest, files number 1
• Move IT in kv/ to explaintest, files number 10
• Move IT in meta/ to explaintest, files number 5
• Move IT in metrics/ to explaintest, files number 1
• Move IT in owner/ to explaintest, files number 2
• Move IT in parser/ to explaintest, files number 34
• Move IT in planner/ to explaintest, files number 81 #47173
• Move IT in plugin/ to explaintest, files number 6
• Move IT in privilege/ to explaintest, files number 4 #47149
• Move IT in resourcemanager/ to explaintest, files number 4
• Move IT in server/ to explaintest, files number 18
• Move IT in session/ to explaintest, files number 11 #47287
• Move IT in sessionctx/ to explaintest, files number 12 #47211
• Move IT in sessiontxn/ to explaintest, files number 10 #47213
• Move IT in statistics/ to integrationtest, files number 19 #47222
• Move IT in store/ to explaintest, files number 29
• Move IT in structure/ to explaintest, files number 1
• Move IT in table/ to explaintest, files number 12 #47160
• Move IT in tablecodec/ to explaintest, files number 3
• Move IT in telemetry/ to explaintest, files number 6
• Move IT in testkit/ to explaintest, files number 2
• Move IT in tests/ to explaintest, files number 30, not include in make ut
• Move IT in tidb-binlog/ to explaintest, files number 4
• Move IT in timer/ to explaintest, files number 9
• Move IT in ttl/ to explaintest, files number 18
• Move IT in types/ to explaintest, files number 24 #46513
• Move IT in util/ to integrationtest, files number 147 #47177

[Defined2014]

Use a shell script to get all *_test.go files in TiDB repo

should_exclude_dir() {
    local dir="$1"

    if [[ "$dir" == "bazel"* ]]; then
        return 0 
    fi

    return 1
}

count_files() {
    local dir="$1"
    local count=0

    while IFS= read -r file; do
        if [ -f "$file" ]; then
            if [[ "$file" == *"/main_test.go" ]]; then
                continue
            fi
            if [[ $count == 0 ]]; then
                echo "Dir：$dir"
            fi
            count=$((count + 1))
            echo "File：$file"
        fi
    done < <(find "$dir" -type f -name "*_test.go")

    if [[ $count -eq 0 ]]; then
        return 1
    fi

    echo "count：$count"
    echo ""
}

for dir in */; do
    if should_exclude_dir "$dir"; then
        continue
    fi

    if ! count_files "$dir"; then
        continue
    fi
done