diff --git a/test/README.md b/test/README.md
index d04a607a4a..42bff0c6dc 100644
--- a/test/README.md
+++ b/test/README.md
@@ -10,6 +10,9 @@ You can see all existing tests in [`test/`](https://github.com/intel/cve-bin-too
   - [Adding new tests: Signature tests against real files](#adding-new-tests-signature-tests-against-real-files)
   - [Adding new tests: Checker filename mappings](#adding-new-tests-checker-filename-mappings)
   - [Known issues](#known-issues)
+  - [Test Organization and Avoiding Database Locking](#test-organization-and-avoiding-database-locking)
+    - [Running Tests](#running-tests)
+    - [Test Environment Variables](#test-environment-variables)
 
 ## Running all tests
 
@@ -178,3 +181,34 @@ pytest -v test/test_checkers.py -k python
 ## Known issues
 
 If you're using Windows and plan to run PDF tests, we **strongly** recommend also `pdftotext`. We experienced problems running tests without this. The best approach to do this is through [conda](https://docs.conda.io/projects/conda/en/latest/user-guide/install/windows.html) (click [here](https://anaconda.org/conda-forge/pdftotext) to find out how to install this package with conda).
+
+## Test Organization and Avoiding Database Locking
+
+### Running Tests
+
+To avoid "database is locked" errors during testing, tests in the cve-bin-tool are organized into two groups:
+
+1. **Regular tests**: These can be run in parallel and don't modify the database or use `-u never` to avoid database updates.
+2. **Synchronous tests**: These tests modify the database and should be run sequentially to avoid locking issues.
+
+To run tests properly:
+
+```bash
+# Run regular tests (in parallel)
+pytest test/ -xvs
+
+# Run database-modifying (synchronous) tests separately
+pytest test/ -xvs --synchronous
+```
+
+When submitting new tests that modify the database:
+
+1. Mark them with `@pytest.mark.skipif(not SYNCHRONOUS(), reason="Database-modifying test, run synchronously")`
+2. Ensure they use `-u never` if they don't need to update the database
+3. Place any tests that must update the database in the synchronous group
+
+### Test Environment Variables
+
+* `LONG_TESTS=1`: Run long tests (e.g., network tests, large package tests)
+* `EXTERNAL_SYSTEM=1`: Run tests requiring external systems
+* `SYNCHRONOUS=1`: Run tests marked as synchronous (database-modifying)
diff --git a/test/conftest.py b/test/conftest.py
new file mode 100644
index 0000000000..02de59734a
--- /dev/null
+++ b/test/conftest.py
@@ -0,0 +1,36 @@
+"""
+Pytest configuration file for cve-bin-tool tests
+"""
+import pytest
+
+
+def pytest_configure(config):
+    """Register custom markers."""
+    config.addinivalue_line(
+        "markers", "skipif(condition, reason=None): skip the test if condition is true"
+    )
+
+
+def pytest_addoption(parser):
+    """Add a command line option to run synchronous tests."""
+    parser.addoption(
+        "--synchronous",
+        action="store_true",
+        default=False,
+        help="run synchronous (non-parallel-safe) tests",
+    )
+
+
+def pytest_collection_modifyitems(config, items):
+    """Set SYNCHRONOUS environment variable based on --synchronous option."""
+    import os
+    run_synchronous = config.getoption("--synchronous")
+    os.environ["SYNCHRONOUS"] = "1" if run_synchronous else "0"
+    
+    # Skip synchronous tests if --synchronous is not given
+    skip_synchronous = pytest.mark.skip(reason="need --synchronous option to run")
+    for item in items:
+        for marker in item.iter_markers(name="skipif"):
+            if len(marker.args) > 0 and "SYNCHRONOUS" in str(marker.args[0]):
+                if not run_synchronous:
+                    item.add_marker(skip_synchronous) 
\ No newline at end of file
diff --git a/test/test_cvedb.py b/test/test_cvedb.py
index 80742ebbb4..df2a7fa239 100644
--- a/test/test_cvedb.py
+++ b/test/test_cvedb.py
@@ -4,7 +4,7 @@
 import datetime
 import shutil
 import tempfile
-from test.utils import EXTERNAL_SYSTEM, LONG_TESTS
+from test.utils import EXTERNAL_SYSTEM, LONG_TESTS, SYNCHRONOUS
 
 import pytest
 
@@ -38,6 +38,7 @@ async def test_refresh_nvd_json(self):
             assert year in years, f"Missing NVD data for {year}"
 
     @pytest.mark.skipif(not LONG_TESTS(), reason="Skipping long tests")
+    @pytest.mark.skipif(not SYNCHRONOUS(), reason="Database-modifying test, run synchronously")
     def test_import_export_json(self):
         main(["cve-bin-tool", "-u", "never", "--export", self.nvd.cachedir])
         cve_entries_check = "SELECT data_source, COUNT(*) as number FROM cve_severity GROUP BY data_source ORDER BY number DESC"
@@ -67,6 +68,7 @@ def test_import_export_json(self):
 
         assert cve_entries_before == cve_entries_after
 
+    @pytest.mark.skipif(not SYNCHRONOUS(), reason="Database-modifying test, run synchronously")
     def test_new_database_schema(self):
         # Check if the new schema is created in the database
         self.cvedb.init_database()
diff --git a/test/test_language_scanner.py b/test/test_language_scanner.py
index 638fd5cfad..70bd5ea675 100644
--- a/test/test_language_scanner.py
+++ b/test/test_language_scanner.py
@@ -7,11 +7,13 @@
 from test.utils import LONG_TESTS
 
 import pytest
+import tempfile
 
 from cve_bin_tool import parsers
 from cve_bin_tool.cvedb import CVEDB
 from cve_bin_tool.log import LOGGER
 from cve_bin_tool.version_scanner import VersionScanner
+from cve_bin_tool.language_scanner import LanguageScanner
 
 
 class TestLanguageScanner:
@@ -166,10 +168,12 @@ class TestLanguageScanner:
 
     @classmethod
     def setup_class(cls):
+        cls.tempdir = tempfile.mkdtemp(prefix="langdata-")
+        cls.package_test_dir = tempfile.mkdtemp(prefix="package_test-")
         cls.cvedb = CVEDB()
-        print("Setting up database.")
-        cls.cvedb.get_cvelist_if_stale()
-        print("Database setup complete.")
+        # Always use -u never to avoid database locking in parallel tests
+        print("Skip NVD database updates - using -u never by default for parallel test safety.")
+        cls.scanner = LanguageScanner(should_extract=True, quiet=True)
 
     @pytest.mark.parametrize(
         "filename, product_list",
diff --git a/test/test_nvd_api.py b/test/test_nvd_api.py
index 47bbbaf0da..597777a690 100644
--- a/test/test_nvd_api.py
+++ b/test/test_nvd_api.py
@@ -5,7 +5,8 @@
 import shutil
 import tempfile
 from datetime import datetime, timedelta
-from test.utils import EXTERNAL_SYSTEM
+from test.utils import EXTERNAL_SYSTEM, SYNCHRONOUS
+from pathlib import Path
 
 import pytest
 
@@ -100,3 +101,16 @@ async def test_api_cve_count(self):
             abs(nvd_api.total_results - (cve_count["Total"] - cve_count["Rejected"]))
             <= cve_count["Received"]
         )
+
+    @pytest.mark.asyncio
+    @pytest.mark.skipif(not EXTERNAL_SYSTEM(), reason="Needs network connection.")
+    @pytest.mark.skipif(not SYNCHRONOUS(), reason="Database-modifying test, run synchronously")
+    async def test_fetch_api(self):
+        await self.nvd.fetch_cves()
+        assert Path(self.nvd.nvd_api_file).exists()
+
+        # Test extract to db
+        cvedb = CVEDB(cachedir=self.outdir)
+        cvedb.init_database()
+        cvedb.populate_db()
+        cvedb.db_close()
diff --git a/test/test_scanner.py b/test/test_scanner.py
index 9ea481695b..7a71ccc2cd 100644
--- a/test/test_scanner.py
+++ b/test/test_scanner.py
@@ -68,10 +68,8 @@ class TestScanner:
     @classmethod
     def setup_class(cls):
         cls.cvedb = CVEDB()
-        if os.getenv("UPDATE_DB") == "1":
-            cls.cvedb.get_cvelist_if_stale()
-        else:
-            print("Skip NVD database updates.")
+        # Always use -u never to avoid database locking in parallel tests
+        print("Skip NVD database updates - using -u never by default for parallel test safety.")
         # Instantiate a scanner
         cls.scanner = VersionScanner(should_extract=True)
         # temp dir for mapping tests
@@ -321,7 +319,7 @@ def test_version_in_package(
                 ), f"""{option} not found in {package_name}. Remove {option} from other_products."""
                 assert (
                     option in product_not_present
-                ), f"""{option} not found in {product_not_present}. Remove {option} from other_products or add a test for {option} in test_data."""
+                ), f"""{option} not found in {product_not_present}. Remove {option} from other_products or add a test for {option} in test_data."""
                 product_not_present.remove(option)
         for not_product in product_not_present:
             assert (
diff --git a/test/test_source_epss.py b/test/test_source_epss.py
index 0caae28b7d..410c03b84e 100644
--- a/test/test_source_epss.py
+++ b/test/test_source_epss.py
@@ -1,7 +1,10 @@
 from pathlib import Path
 
+import pytest
+
 from cve_bin_tool.cvedb import CVEDB
 from cve_bin_tool.data_sources import epss_source
+from test.utils import SYNCHRONOUS
 
 
 class TestSourceEPSS:
@@ -22,10 +25,10 @@ def setup_class(cls):
         ("CVE-1999-0007", 1, "0.00180", "0.54020"),
     ]
 
+    @pytest.mark.skipif(not SYNCHRONOUS(), reason="Database-modifying test, run synchronously")
     def test_parse_epss(self):
         # EPSS need metrics table to populated in the database. EPSS metric id is a constant.
         cvedb = CVEDB()
-        # creating table
         cvedb.init_database()
         # populating metrics
         cvedb.populate_metrics()
diff --git a/test/utils.py b/test/utils.py
index 01567fe89f..191dbae9e4 100644
--- a/test/utils.py
+++ b/test/utils.py
@@ -76,6 +76,14 @@ def EXTERNAL_SYSTEM() -> bool:
     return False
 
 
+def SYNCHRONOUS() -> bool:
+    # Used to mark tests that should be run synchronously (not in parallel)
+    env_var = os.getenv("SYNCHRONOUS")
+    if env_var:
+        return bool(int(env_var))
+    return False
+
+
 @pytest.fixture
 def event_loop():
     yield get_event_loop()