diff --git a/tests/system_tests/CFortranInterop/test_CFortranInterop.py b/tests/system_tests/CFortranInterop/test_CFortranInterop.py
index 5e7b9067..483b6968 100644
--- a/tests/system_tests/CFortranInterop/test_CFortranInterop.py
+++ b/tests/system_tests/CFortranInterop/test_CFortranInterop.py
@@ -17,6 +17,7 @@
 from fab.steps.link import link_exe
 from fab.steps.preprocess import preprocess_fortran, preprocess_c
 
+import pytest
 
 PROJECT_SOURCE = Path(__file__).parent / 'project-source'
 
@@ -24,7 +25,8 @@
 def test_CFortranInterop(tmp_path):
 
     # build
-    with BuildConfig(fab_workspace=tmp_path, project_label='foo', multiprocessing=False) as config:
+    with BuildConfig(fab_workspace=tmp_path, project_label='foo', multiprocessing=False) as config, \
+         pytest.warns(UserWarning, match="removing managed flag"):
 
         grab_folder(config, src=PROJECT_SOURCE),
         find_source_files(config),
diff --git a/tests/system_tests/FortranDependencies/test_FortranDependencies.py b/tests/system_tests/FortranDependencies/test_FortranDependencies.py
index 48932b5c..6971bf83 100644
--- a/tests/system_tests/FortranDependencies/test_FortranDependencies.py
+++ b/tests/system_tests/FortranDependencies/test_FortranDependencies.py
@@ -17,11 +17,14 @@
 from fab.steps.link import link_exe
 from fab.steps.preprocess import preprocess_fortran
 
+import pytest
+
 
 def test_FortranDependencies(tmp_path):
 
     # build
-    with BuildConfig(fab_workspace=tmp_path, project_label='foo', multiprocessing=False) as config:
+    with BuildConfig(fab_workspace=tmp_path, project_label='foo', multiprocessing=False) as config, \
+         pytest.warns(UserWarning, match="removing managed flag"):
         grab_folder(config, src=Path(__file__).parent / 'project-source'),
         find_source_files(config),
         preprocess_fortran(config),  # nothing to preprocess, actually, it's all little f90 files
diff --git a/tests/system_tests/FortranPreProcess/test_FortranPreProcess.py b/tests/system_tests/FortranPreProcess/test_FortranPreProcess.py
index 49652641..f45ea74c 100644
--- a/tests/system_tests/FortranPreProcess/test_FortranPreProcess.py
+++ b/tests/system_tests/FortranPreProcess/test_FortranPreProcess.py
@@ -15,9 +15,12 @@
 from fab.steps.link import link_exe
 from fab.steps.preprocess import preprocess_fortran
 
+import pytest
+
 
 def build(fab_workspace, fpp_flags=None):
-    with BuildConfig(fab_workspace=fab_workspace, project_label='foo', multiprocessing=False) as config:
+    with BuildConfig(fab_workspace=fab_workspace, project_label='foo', multiprocessing=False) as config, \
+         pytest.warns(UserWarning, match="removing managed flag"):
         grab_folder(config, Path(__file__).parent / 'project-source'),
         find_source_files(config),
         preprocess_fortran(config, common_flags=fpp_flags),
diff --git a/tests/system_tests/MinimalFortran/test_MinimalFortran.py b/tests/system_tests/MinimalFortran/test_MinimalFortran.py
index 66fb221a..6dd7615f 100644
--- a/tests/system_tests/MinimalFortran/test_MinimalFortran.py
+++ b/tests/system_tests/MinimalFortran/test_MinimalFortran.py
@@ -15,13 +15,16 @@
 from fab.steps.link import link_exe
 from fab.steps.preprocess import preprocess_fortran
 
+import pytest
+
 PROJECT_SOURCE = Path(__file__).parent / 'project-source'
 
 
 def test_MinimalFortran(tmp_path):
 
     # build
-    with BuildConfig(fab_workspace=tmp_path, project_label='foo', multiprocessing=False) as config:
+    with BuildConfig(fab_workspace=tmp_path, project_label='foo', multiprocessing=False) as config, \
+         pytest.warns(UserWarning, match="removing managed flag"):
         grab_folder(config, PROJECT_SOURCE),
         find_source_files(config),
         preprocess_fortran(config),
diff --git a/tests/system_tests/git/test_git.py b/tests/system_tests/git/test_git.py
index dabbc137..32895dfe 100644
--- a/tests/system_tests/git/test_git.py
+++ b/tests/system_tests/git/test_git.py
@@ -38,21 +38,25 @@ def url(self):
         return 'https://github.com/metomi/fab-test-data.git'
 
     def test_checkout_url(self, tmp_path, url, config):
-        git_checkout(config, src=url, dst_label='tiny_fortran')
-        # todo: The commit will keep changing. Perhaps make a non-changing branch
-        assert current_commit(config.source_root / 'tiny_fortran') == '3cba55e'
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            git_checkout(config, src=url, dst_label='tiny_fortran')
+            # todo: The commit will keep changing. Perhaps make a non-changing branch
+            assert current_commit(config.source_root / 'tiny_fortran') == '3cba55e'
 
     def test_checkout_branch(self, tmp_path, url, config):
-        git_checkout(config, src=url, dst_label='tiny_fortran', revision='main')
-        assert current_commit(config.source_root / 'tiny_fortran') == '3cba55e'
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            git_checkout(config, src=url, dst_label='tiny_fortran', revision='main')
+            assert current_commit(config.source_root / 'tiny_fortran') == '3cba55e'
 
     def test_checkout_tag(self, tmp_path, url, config):
-        git_checkout(config, src=url, dst_label='tiny_fortran', revision='early')
-        assert current_commit(config.source_root / 'tiny_fortran') == 'ee56489'
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            git_checkout(config, src=url, dst_label='tiny_fortran', revision='early')
+            assert current_commit(config.source_root / 'tiny_fortran') == 'ee56489'
 
     def test_checkout_commit(self, tmp_path, url, config):
-        git_checkout(config, src=url, dst_label='tiny_fortran', revision='ee5648928893701c5dbccdbf0561c0038352a5ff')
-        assert current_commit(config.source_root / 'tiny_fortran') == 'ee56489'
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            git_checkout(config, src=url, dst_label='tiny_fortran', revision='ee5648928893701c5dbccdbf0561c0038352a5ff')
+            assert current_commit(config.source_root / 'tiny_fortran') == 'ee56489'
 
 
 # todo: we could do with a test to ensure left-over files from previous fetches are cleaned away
@@ -65,18 +69,25 @@ def repo_url(self, tmp_path):
         shutil.unpack_archive(Path(__file__).parent / 'repo.tar.gz', tmp_path)
         return f'file://{tmp_path}/repo'
 
+    @pytest.mark.filterwarnings("ignore: Python 3.14 will, "
+                                "by default, filter extracted tar archives "
+                                "and reject files or modify their metadata. "
+                                "Use the filter argument to control this behavior.")
     def test_vanilla(self, repo_url, config):
 
         # checkout master
-        git_checkout(config, src=repo_url, dst_label='tiny_fortran', revision='master')
-        check_file = config.source_root / 'tiny_fortran/file1.txt'
-        assert 'This is sentence one in file one.' in open(check_file).read()
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            git_checkout(config, src=repo_url, dst_label='tiny_fortran', revision='master')
+            check_file = config.source_root / 'tiny_fortran/file1.txt'
+            assert 'This is sentence one in file one.' in open(check_file).read()
 
-        git_merge(config, src=repo_url, dst_label='tiny_fortran', revision='experiment_a')
-        assert 'This is sentence one, with Experiment A modification.' in open(check_file).read()
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            git_merge(config, src=repo_url, dst_label='tiny_fortran', revision='experiment_a')
+            assert 'This is sentence one, with Experiment A modification.' in open(check_file).read()
 
         with pytest.raises(RuntimeError):
             git_merge(config, src=repo_url, dst_label='tiny_fortran', revision='experiment_b')
 
         # The conflicted merge must have been aborted, check that we can do another checkout of master
-        git_checkout(config, src=repo_url, dst_label='tiny_fortran', revision='master')
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            git_checkout(config, src=repo_url, dst_label='tiny_fortran', revision='master')
diff --git a/tests/system_tests/grab_archive/test_grab_archive.py b/tests/system_tests/grab_archive/test_grab_archive.py
index 73d7543e..aa4251ea 100644
--- a/tests/system_tests/grab_archive/test_grab_archive.py
+++ b/tests/system_tests/grab_archive/test_grab_archive.py
@@ -8,11 +8,14 @@
 
 from fab.steps.grab.archive import grab_archive
 
+import pytest
+
 
 class TestGrabArchive(object):
 
     def test(self, tmp_path):
-        tar_file = Path(__file__).parent / '../git/tiny_fortran.tar'
-        grab_archive(config=mock.Mock(source_root=tmp_path), src=tar_file)
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            tar_file = Path(__file__).parent / '../git/tiny_fortran.tar'
+            grab_archive(config=mock.Mock(source_root=tmp_path), src=tar_file)
 
-        assert (tmp_path / 'tiny_fortran/src/my_mod.F90').exists()
+            assert (tmp_path / 'tiny_fortran/src/my_mod.F90').exists()
diff --git a/tests/system_tests/psyclone/test_psyclone_system_test.py b/tests/system_tests/psyclone/test_psyclone_system_test.py
index b033573d..20cd7761 100644
--- a/tests/system_tests/psyclone/test_psyclone_system_test.py
+++ b/tests/system_tests/psyclone/test_psyclone_system_test.py
@@ -173,20 +173,20 @@ def test_run(self, config):
         # So use a list instead:
         assert all(list(config.prebuild_folder.glob(f)) == [] for f in expect_prebuild_files)
         assert all(list(config.build_output.glob(f)) == [] for f in expect_build_files)
-        with config:
+        with config, pytest.warns(UserWarning, match="no transformation script specified"):
             self.steps(config)
         assert all(list(config.prebuild_folder.glob(f)) != [] for f in expect_prebuild_files)
         assert all(list(config.build_output.glob(f)) != [] for f in expect_build_files)
 
     def test_prebuild(self, tmp_path, config):
-        with config:
+        with config, pytest.warns(UserWarning, match="no transformation script specified"):
             self.steps(config)
 
         # make sure no work gets done the second time round
         with mock.patch('fab.parse.x90.X90Analyser.walk_nodes') as mock_x90_walk:
             with mock.patch('fab.parse.fortran.FortranAnalyser.walk_nodes') as mock_fortran_walk:
                 with mock.patch('fab.steps.psyclone.run_psyclone') as mock_run:
-                    with config:
+                    with config, pytest.warns(UserWarning, match="no transformation script specified"):
                         self.steps(config)
 
         mock_x90_walk.assert_not_called()
diff --git a/tests/system_tests/svn_fcm/test_svn_fcm_system_test.py b/tests/system_tests/svn_fcm/test_svn_fcm_system_test.py
index 532c5cac..da2de348 100644
--- a/tests/system_tests/svn_fcm/test_svn_fcm_system_test.py
+++ b/tests/system_tests/svn_fcm/test_svn_fcm_system_test.py
@@ -110,23 +110,34 @@ class TestExport(object):
 
     # Run the test twice, once with SvnExport and once with FcmExport - depending on which tools are available.
     @pytest.mark.parametrize('export_func', export_funcs)
+    @pytest.mark.filterwarnings("ignore: Python 3.14 will, "
+                                "by default, filter extracted tar archives "
+                                "and reject files or modify their metadata. "
+                                "Use the filter argument to control this behavior.")
     def test_export(self, file2_experiment, config, export_func):
         # Export the "file 2 experiment" branch, which has different sentence from trunk in r1 and r2
-        export_func(config, src=file2_experiment, dst_label='proj', revision=7)
-        assert confirm_file2_experiment_r7(config)
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            export_func(config, src=file2_experiment, dst_label='proj', revision=7)
+            assert confirm_file2_experiment_r7(config)
 
         # Make sure we can export twice into the same folder.
         # Todo: should the export step wipe the destination first? To remove residual, orphaned files?
-        export_func(config, src=file2_experiment, dst_label='proj', revision=8)
-        assert confirm_file2_experiment_r8(config)
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            export_func(config, src=file2_experiment, dst_label='proj', revision=8)
+            assert confirm_file2_experiment_r8(config)
 
 
+@pytest.mark.filterwarnings("ignore: Python 3.14 will, "
+                            "by default, filter extracted tar archives "
+                            "and reject files or modify their metadata. "
+                            "Use the filter argument to control this behavior.")
 class TestCheckout(object):
 
     @pytest.mark.parametrize('checkout_func', checkout_funcs)
     def test_new_folder(self, trunk, config, checkout_func):
-        checkout_func(config, src=trunk, dst_label='proj')
-        assert confirm_trunk(config)
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            checkout_func(config, src=trunk, dst_label='proj')
+            assert confirm_trunk(config)
 
     @pytest.mark.parametrize('checkout_func', checkout_funcs)
     def test_working_copy(self, file2_experiment, config, checkout_func):
@@ -143,7 +154,8 @@ def test_working_copy(self, file2_experiment, config, checkout_func):
         else:
             assert False
 
-        with mock.patch('fab.steps.grab.svn.run_command', wraps=fab.steps.grab.svn.run_command) as wrap:
+        with mock.patch('fab.steps.grab.svn.run_command', wraps=fab.steps.grab.svn.run_command) as wrap, \
+             pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
 
             checkout_func(config, src=file2_experiment, dst_label='proj', revision='7')
             assert confirm_file2_experiment_r7(config)
@@ -160,38 +172,46 @@ def test_working_copy(self, file2_experiment, config, checkout_func):
     @pytest.mark.parametrize('export_func,checkout_func', zip(export_funcs, checkout_funcs))
     def test_not_working_copy(self, trunk, config, export_func, checkout_func):
         # the export command just makes files, not a working copy
-        export_func(config, src=trunk, dst_label='proj')
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            export_func(config, src=trunk, dst_label='proj')
 
         # if we try to checkout into that folder, it should fail
         with pytest.raises(ValueError):
             checkout_func(config, src=trunk, dst_label='proj')
 
 
+@pytest.mark.filterwarnings("ignore: Python 3.14 will, "
+                            "by default, filter extracted tar archives "
+                            "and reject files or modify their metadata. "
+                            "Use the filter argument to control this behavior.")
 class TestMerge(object):
 
     @pytest.mark.parametrize('checkout_func,merge_func', zip(checkout_funcs, merge_funcs))
     def test_vanilla(self, trunk, file2_experiment, config, checkout_func, merge_func):
-        # something to merge into; checkout trunk
-        checkout_func(config, src=trunk, dst_label='proj')
-        confirm_trunk(config)
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            # something to merge into; checkout trunk
+            checkout_func(config, src=trunk, dst_label='proj')
+            confirm_trunk(config)
 
-        # merge another branch in
-        merge_func(config, src=file2_experiment, dst_label='proj')
-        confirm_file2_experiment_r8(config)
+            # merge another branch in
+            merge_func(config, src=file2_experiment, dst_label='proj')
+            confirm_file2_experiment_r8(config)
 
     @pytest.mark.parametrize('checkout_func,merge_func', zip(checkout_funcs, merge_funcs))
     def test_revision(self, trunk, file2_experiment, config, checkout_func, merge_func):
-        # something to merge into; checkout trunk
-        checkout_func(config, src=trunk, dst_label='proj')
-        confirm_trunk(config)
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            # something to merge into; checkout trunk
+            checkout_func(config, src=trunk, dst_label='proj')
+            confirm_trunk(config)
 
-        # merge another branch in
-        merge_func(config, src=file2_experiment, dst_label='proj', revision=7)
-        confirm_file2_experiment_r7(config)
+            # merge another branch in
+            merge_func(config, src=file2_experiment, dst_label='proj', revision=7)
+            confirm_file2_experiment_r7(config)
 
     @pytest.mark.parametrize('export_func,merge_func', zip(export_funcs, merge_funcs))
     def test_not_working_copy(self, trunk, file2_experiment, config, export_func, merge_func):
-        export_func(config, src=trunk, dst_label='proj')
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            export_func(config, src=trunk, dst_label='proj')
 
         # try to merge into an export
         with pytest.raises(ValueError):
@@ -199,8 +219,9 @@ def test_not_working_copy(self, trunk, file2_experiment, config, export_func, me
 
     @pytest.mark.parametrize('checkout_func,merge_func', zip(checkout_funcs, merge_funcs))
     def test_conflict(self, file1_experiment_a, file1_experiment_b, config, checkout_func, merge_func):
-        checkout_func(config, src=file1_experiment_a, dst_label='proj')
-        confirm_file1_experiment_a(config)
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            checkout_func(config, src=file1_experiment_a, dst_label='proj')
+            confirm_file1_experiment_a(config)
 
         # this branch modifies the same line of text
         with pytest.raises(RuntimeError):
@@ -208,11 +229,12 @@ def test_conflict(self, file1_experiment_a, file1_experiment_b, config, checkout
 
     @pytest.mark.parametrize('checkout_func,merge_func', zip(checkout_funcs, merge_funcs))
     def test_multiple_merges(self, trunk, file1_experiment_a, file2_experiment, config, checkout_func, merge_func):
-        checkout_func(config, src=trunk, dst_label='proj')
-        confirm_trunk(config)
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            checkout_func(config, src=trunk, dst_label='proj')
+            confirm_trunk(config)
 
-        merge_func(config, src=file1_experiment_a, dst_label='proj')
-        confirm_file1_experiment_a(config)
+            merge_func(config, src=file1_experiment_a, dst_label='proj')
+            confirm_file1_experiment_a(config)
 
-        merge_func(config, src=file2_experiment, dst_label='proj', revision=7)
-        confirm_file2_experiment_r7(config)
+            merge_func(config, src=file2_experiment, dst_label='proj', revision=7)
+            confirm_file2_experiment_r7(config)
diff --git a/tests/system_tests/zero_config/test_zero_config.py b/tests/system_tests/zero_config/test_zero_config.py
index 704c0b93..5ae56b3d 100644
--- a/tests/system_tests/zero_config/test_zero_config.py
+++ b/tests/system_tests/zero_config/test_zero_config.py
@@ -5,29 +5,33 @@
 import os
 from unittest import mock
 
+import pytest
+
 
 class TestZeroConfig(object):
 
     def test_fortran_dependencies(self, tmp_path):
         # test the sample project in the fortran dependencies system test
-        kwargs = {'project_label': 'fortran deps test', 'fab_workspace': tmp_path, 'multiprocessing': False}
+        with pytest.warns(DeprecationWarning, match="RootIncFiles is deprecated as .inc files are due to be removed."):
+            kwargs = {'project_label': 'fortran deps test', 'fab_workspace': tmp_path, 'multiprocessing': False}
 
-        config = cli_fab(
-            folder=Path(__file__).parent.parent / 'FortranDependencies',
-            kwargs=kwargs)
+            config = cli_fab(
+                folder=Path(__file__).parent.parent / 'FortranDependencies',
+                kwargs=kwargs)
 
-        assert (config.project_workspace / 'first').exists()
-        assert (config.project_workspace / 'second').exists()
+            assert (config.project_workspace / 'first').exists()
+            assert (config.project_workspace / 'second').exists()
 
     def test_c_fortran_interop(self, tmp_path):
         # test the sample project in the fortran dependencies system test
-        kwargs = {'project_label': 'CFInterop test', 'fab_workspace': tmp_path, 'multiprocessing': 'False'}
+        with pytest.warns(DeprecationWarning, match="RootIncFiles is deprecated as .inc files are due to be removed."):
+            kwargs = {'project_label': 'CFInterop test', 'fab_workspace': tmp_path, 'multiprocessing': 'False'}
 
-        config = cli_fab(
-            folder=Path(__file__).parent.parent / 'CFortranInterop',
-            kwargs=kwargs)
+            config = cli_fab(
+                folder=Path(__file__).parent.parent / 'CFortranInterop',
+                kwargs=kwargs)
 
-        assert (config.project_workspace / 'main').exists()
+            assert (config.project_workspace / 'main').exists()
 
     def test_fortran_explicit_gfortran(self, tmp_path):
         # test the sample project in the fortran dependencies system test
@@ -36,7 +40,8 @@ def test_fortran_explicit_gfortran(self, tmp_path):
         cc = shutil.which('gcc')
         fc = shutil.which('gfortran')
 
-        with mock.patch.dict(os.environ, CC=cc, FC=fc, LD=fc):
+        with mock.patch.dict(os.environ, CC=cc, FC=fc, LD=fc), \
+             pytest.warns(DeprecationWarning, match="RootIncFiles is deprecated as .inc files are due to be removed."):
             config = cli_fab(
                 folder=Path(__file__).parent.parent / 'CFortranInterop',
                 kwargs=kwargs)
diff --git a/tests/unit_tests/steps/test_analyse.py b/tests/unit_tests/steps/test_analyse.py
index 7405939c..0e1db71b 100644
--- a/tests/unit_tests/steps/test_analyse.py
+++ b/tests/unit_tests/steps/test_analyse.py
@@ -115,7 +115,10 @@ class Test_parse_files(object):
 
     def test_exceptions(self, tmp_path):
         # make sure parse exceptions do not stop the build
-        with mock.patch('fab.steps.run_mp', return_value=[(Exception('foo'), None)]):
+        with mock.patch('fab.steps.run_mp', return_value=[(Exception('foo'), None)]), \
+             pytest.warns(UserWarning, match="deprecated 'DEPENDS ON:'"):
+            # The warning "deprecated 'DEPENDS ON:' comment found in fortran code"
+            # is in "def _parse_files" in "source/steps/analyse.py"
             config = BuildConfig('proj', fab_workspace=tmp_path)
 
             # the exception should be suppressed (and logged) and this step should run to completion
@@ -130,7 +133,10 @@ def test_vanilla(self):
         workaround = FortranParserWorkaround(fpath=Path('foo.f'), symbol_defs={'foo', })
         analysed_files = set()
 
-        with mock.patch('fab.parse.fortran.file_checksum', return_value=HashedFile(None, 123)):
+        with mock.patch('fab.parse.fortran.file_checksum', return_value=HashedFile(None, 123)), \
+             pytest.warns(UserWarning, match="SPECIAL MEASURE: injecting user-defined analysis results"):
+            # This warning "UserWarning: SPECIAL MEASURE: injecting user-defined analysis results"
+            # is in "def _add_manual_results" in "source/steps/analyse.py"
             _add_manual_results(special_measure_analysis_results=[workaround], analysed_files=analysed_files)
 
         assert analysed_files == {AnalysedFortran(fpath=Path('foo.f'), file_hash=123, symbol_defs={'foo', })}
diff --git a/tests/unit_tests/steps/test_archive_objects.py b/tests/unit_tests/steps/test_archive_objects.py
index 2d7ab1bb..0600d85c 100644
--- a/tests/unit_tests/steps/test_archive_objects.py
+++ b/tests/unit_tests/steps/test_archive_objects.py
@@ -5,6 +5,8 @@
 from fab.constants import OBJECT_FILES, OBJECT_ARCHIVES
 from fab.steps.archive_objects import archive_objects
 
+import pytest
+
 
 class Test_archive_objects(object):
 
@@ -15,7 +17,8 @@ def test_for_exes(self):
         config = BuildConfig('proj')
         config._artefact_store = {OBJECT_FILES: {target: [f'{target}.o', 'util.o'] for target in targets}}
 
-        with mock.patch('fab.steps.archive_objects.run_command') as mock_run_command:
+        with mock.patch('fab.steps.archive_objects.run_command') as mock_run_command, \
+             pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
             archive_objects(config=config)
 
         # ensure the correct command line calls were made
@@ -36,7 +39,8 @@ def test_for_library(self):
         config = BuildConfig('proj')
         config._artefact_store = {OBJECT_FILES: {None: ['util1.o', 'util2.o']}}
 
-        with mock.patch('fab.steps.archive_objects.run_command') as mock_run_command:
+        with mock.patch('fab.steps.archive_objects.run_command') as mock_run_command, \
+             pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
             archive_objects(config=config, output_fpath=config.build_output / 'mylib.a')
 
         # ensure the correct command line calls were made
diff --git a/tests/unit_tests/steps/test_cleanup_prebuilds.py b/tests/unit_tests/steps/test_cleanup_prebuilds.py
index 21cddb63..ec15acc7 100644
--- a/tests/unit_tests/steps/test_cleanup_prebuilds.py
+++ b/tests/unit_tests/steps/test_cleanup_prebuilds.py
@@ -18,7 +18,8 @@
 class TestCleanupPrebuilds(object):
 
     def test_init_no_args(self):
-        with mock.patch('fab.steps.cleanup_prebuilds.file_walk', return_value=[Path('foo.o')]):
+        with mock.patch('fab.steps.cleanup_prebuilds.file_walk', return_value=[Path('foo.o')]), \
+             pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
             with mock.patch('fab.steps.cleanup_prebuilds.remove_all_unused') as mock_remove_all_unused:
                 cleanup_prebuilds(config=mock.Mock(_artefact_store={CURRENT_PREBUILDS: [Path('bar.o')]}))
         mock_remove_all_unused.assert_called_once_with(found_files=[Path('foo.o')], current_files=[Path('bar.o')])
diff --git a/tests/unit_tests/steps/test_compile_c.py b/tests/unit_tests/steps/test_compile_c.py
index 9855f3d7..13f20223 100644
--- a/tests/unit_tests/steps/test_compile_c.py
+++ b/tests/unit_tests/steps/test_compile_c.py
@@ -36,7 +36,8 @@ def test_vanilla(self, content):
                 send_metric=DEFAULT,
                 get_compiler_version=mock.Mock(return_value='1.2.3')) as values:
             with mock.patch('pathlib.Path.mkdir'):
-                with mock.patch.dict(os.environ, {'CC': 'foo_cc', 'CFLAGS': '-Denv_flag'}):
+                with mock.patch.dict(os.environ, {'CC': 'foo_cc', 'CFLAGS': '-Denv_flag'}), \
+                     pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                     compile_c(
                         config=config, path_flags=[AddFlags(match='$source/*', flags=['-I', 'foo/include', '-Dhello'])])
 
diff --git a/tests/unit_tests/steps/test_compile_fortran.py b/tests/unit_tests/steps/test_compile_fortran.py
index a2a0c3cd..7f42662a 100644
--- a/tests/unit_tests/steps/test_compile_fortran.py
+++ b/tests/unit_tests/steps/test_compile_fortran.py
@@ -182,7 +182,8 @@ def test_without_prebuild(self):
 
         with mock.patch('pathlib.Path.exists', return_value=False):  # no output files exist
             with mock.patch('fab.steps.compile_fortran.compile_file') as mock_compile_file:
-                with mock.patch('shutil.copy2') as mock_copy:
+                with mock.patch('shutil.copy2') as mock_copy, \
+                     pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                     res, artefacts = process_file((analysed_file, mp_common_args))
 
         # check we got the expected compilation result
@@ -210,7 +211,8 @@ def test_with_prebuild(self):
 
         with mock.patch('pathlib.Path.exists', return_value=True):  # mod def files and obj file all exist
             with mock.patch('fab.steps.compile_fortran.compile_file') as mock_compile_file:
-                with mock.patch('shutil.copy2') as mock_copy:
+                with mock.patch('shutil.copy2') as mock_copy, \
+                     pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                     res, artefacts = process_file((analysed_file, mp_common_args))
 
         expect_object_fpath = Path(f'/fab/proj/build_output/_prebuild/foofile.{obj_combo_hash}.o')
@@ -238,7 +240,8 @@ def test_file_hash(self):
 
         with mock.patch('pathlib.Path.exists', side_effect=[True, True, False]):  # mod files exist, obj file doesn't
             with mock.patch('fab.steps.compile_fortran.compile_file') as mock_compile_file:
-                with mock.patch('shutil.copy2') as mock_copy:
+                with mock.patch('shutil.copy2') as mock_copy, \
+                     pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                     res, artefacts = process_file((analysed_file, mp_common_args))
 
         expect_object_fpath = Path(f'/fab/proj/build_output/_prebuild/foofile.{obj_combo_hash}.o')
@@ -262,7 +265,8 @@ def test_flags_hash(self):
 
         with mock.patch('pathlib.Path.exists', side_effect=[True, True, False]):  # mod files exist, obj file doesn't
             with mock.patch('fab.steps.compile_fortran.compile_file') as mock_compile_file:
-                with mock.patch('shutil.copy2') as mock_copy:
+                with mock.patch('shutil.copy2') as mock_copy, \
+                     pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                     res, artefacts = process_file((analysed_file, mp_common_args))
 
         expect_object_fpath = Path(f'/fab/proj/build_output/_prebuild/foofile.{obj_combo_hash}.o')
@@ -290,7 +294,8 @@ def test_deps_hash(self):
 
         with mock.patch('pathlib.Path.exists', side_effect=[True, True, False]):  # mod files exist, obj file doesn't
             with mock.patch('fab.steps.compile_fortran.compile_file') as mock_compile_file:
-                with mock.patch('shutil.copy2') as mock_copy:
+                with mock.patch('shutil.copy2') as mock_copy, \
+                     pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                     res, artefacts = process_file((analysed_file, mp_common_args))
 
         expect_object_fpath = Path(f'/fab/proj/build_output/_prebuild/foofile.{obj_combo_hash}.o')
@@ -317,7 +322,8 @@ def test_compiler_hash(self):
 
         with mock.patch('pathlib.Path.exists', side_effect=[True, True, False]):  # mod files exist, obj file doesn't
             with mock.patch('fab.steps.compile_fortran.compile_file') as mock_compile_file:
-                with mock.patch('shutil.copy2') as mock_copy:
+                with mock.patch('shutil.copy2') as mock_copy, \
+                     pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                     res, artefacts = process_file((analysed_file, mp_common_args))
 
         expect_object_fpath = Path(f'/fab/proj/build_output/_prebuild/foofile.{obj_combo_hash}.o')
@@ -344,7 +350,8 @@ def test_compiler_version_hash(self):
 
         with mock.patch('pathlib.Path.exists', side_effect=[True, True, False]):  # mod files exist, obj file doesn't
             with mock.patch('fab.steps.compile_fortran.compile_file') as mock_compile_file:
-                with mock.patch('shutil.copy2') as mock_copy:
+                with mock.patch('shutil.copy2') as mock_copy, \
+                     pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                     res, artefacts = process_file((analysed_file, mp_common_args))
 
         expect_object_fpath = Path(f'/fab/proj/build_output/_prebuild/foofile.{obj_combo_hash}.o')
@@ -367,7 +374,8 @@ def test_mod_missing(self):
 
         with mock.patch('pathlib.Path.exists', side_effect=[False, True, True]):  # one mod file missing
             with mock.patch('fab.steps.compile_fortran.compile_file') as mock_compile_file:
-                with mock.patch('shutil.copy2') as mock_copy:
+                with mock.patch('shutil.copy2') as mock_copy, \
+                     pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                     res, artefacts = process_file((analysed_file, mp_common_args))
 
         expect_object_fpath = Path(f'/fab/proj/build_output/_prebuild/foofile.{obj_combo_hash}.o')
@@ -390,7 +398,8 @@ def test_obj_missing(self):
 
         with mock.patch('pathlib.Path.exists', side_effect=[True, True, False]):  # object file missing
             with mock.patch('fab.steps.compile_fortran.compile_file') as mock_compile_file:
-                with mock.patch('shutil.copy2') as mock_copy:
+                with mock.patch('shutil.copy2') as mock_copy, \
+                     pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                     res, artefacts = process_file((analysed_file, mp_common_args))
 
         expect_object_fpath = Path(f'/fab/proj/build_output/_prebuild/foofile.{obj_combo_hash}.o')
@@ -426,14 +435,16 @@ def test_with_flags(self):
 
     def test_gfortran_managed_flags(self):
         with mock.patch.dict(os.environ, FC='gfortran -c', FFLAGS='-J /mods'):
-            with mock.patch('fab.steps.compile_fortran.get_compiler_version'):
+            with mock.patch('fab.steps.compile_fortran.get_compiler_version'), \
+                 pytest.warns(UserWarning, match="removing managed flag"):
                 compiler, compiler_version, flags = handle_compiler_args()
         assert compiler == 'gfortran'
         assert flags.common_flags == []
 
     def test_ifort_managed_flags(self):
         with mock.patch.dict(os.environ, FC='ifort -c', FFLAGS='-module /mods'):
-            with mock.patch('fab.steps.compile_fortran.get_compiler_version'):
+            with mock.patch('fab.steps.compile_fortran.get_compiler_version'), \
+                 pytest.warns(UserWarning, match="removing managed flag"):
                 compiler, compiler_version, flags = handle_compiler_args()
         assert compiler == 'ifort'
         assert flags.common_flags == []
diff --git a/tests/unit_tests/steps/test_grab.py b/tests/unit_tests/steps/test_grab.py
index 409b1fa9..57878b22 100644
--- a/tests/unit_tests/steps/test_grab.py
+++ b/tests/unit_tests/steps/test_grab.py
@@ -10,14 +10,18 @@
 from fab.steps.grab.fcm import fcm_export
 from fab.steps.grab.folder import grab_folder
 
+import pytest
+
 
 class TestGrabFolder(object):
 
     def test_trailing_slash(self):
-        self._common(grab_src='/grab/source/', expect_grab_src='/grab/source/')
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            self._common(grab_src='/grab/source/', expect_grab_src='/grab/source/')
 
     def test_no_trailing_slash(self):
-        self._common(grab_src='/grab/source', expect_grab_src='/grab/source/')
+        with pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
+            self._common(grab_src='/grab/source', expect_grab_src='/grab/source/')
 
     def _common(self, grab_src, expect_grab_src):
         source_root = Path('/workspace/source')
@@ -41,7 +45,8 @@ def test_no_revision(self):
 
         mock_config = SimpleNamespace(source_root=source_root)
         with mock.patch('pathlib.Path.mkdir'):
-            with mock.patch('fab.steps.grab.svn.run_command') as mock_run:
+            with mock.patch('fab.steps.grab.svn.run_command') as mock_run, \
+                 pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                 fcm_export(config=mock_config, src=source_url, dst_label=dst_label)
 
         mock_run.assert_called_once_with(['fcm', 'export', '--force', source_url, str(source_root / dst_label)])
@@ -54,7 +59,8 @@ def test_revision(self):
 
         mock_config = SimpleNamespace(source_root=source_root)
         with mock.patch('pathlib.Path.mkdir'):
-            with mock.patch('fab.steps.grab.svn.run_command') as mock_run:
+            with mock.patch('fab.steps.grab.svn.run_command') as mock_run, \
+                 pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                 fcm_export(mock_config, src=source_url, dst_label=dst_label, revision=revision)
 
         mock_run.assert_called_once_with(
diff --git a/tests/unit_tests/steps/test_link.py b/tests/unit_tests/steps/test_link.py
index b7e3fd5e..cfee8f9a 100644
--- a/tests/unit_tests/steps/test_link.py
+++ b/tests/unit_tests/steps/test_link.py
@@ -10,6 +10,8 @@
 from fab.constants import OBJECT_FILES
 from fab.steps.link import link_exe
 
+import pytest
+
 
 class TestLinkExe(object):
     def test_run(self):
@@ -21,7 +23,8 @@ def test_run(self):
         )
 
         with mock.patch('os.getenv', return_value='-L/foo1/lib -L/foo2/lib'):
-            with mock.patch('fab.steps.link.run_command') as mock_run:
+            with mock.patch('fab.steps.link.run_command') as mock_run, \
+                 pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                 link_exe(config, linker='foolink', flags=['-fooflag', '-barflag'])
 
         mock_run.assert_called_with([
diff --git a/tests/unit_tests/steps/test_root_inc_files.py b/tests/unit_tests/steps/test_root_inc_files.py
index e3037cce..3bb55cee 100644
--- a/tests/unit_tests/steps/test_root_inc_files.py
+++ b/tests/unit_tests/steps/test_root_inc_files.py
@@ -17,7 +17,8 @@ def test_vanilla(self):
         config._artefact_store['all_source'] = inc_files
 
         with mock.patch('fab.steps.root_inc_files.shutil') as mock_shutil:
-            with mock.patch('fab.steps.root_inc_files.Path.mkdir'):
+            with mock.patch('fab.steps.root_inc_files.Path.mkdir'), \
+                 pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                 root_inc_files(config)
 
         mock_shutil.copy.assert_called_once_with(inc_files[0], config.build_output)
@@ -29,7 +30,8 @@ def test_skip_output_folder(self):
         config._artefact_store['all_source'] = inc_files
 
         with mock.patch('fab.steps.root_inc_files.shutil') as mock_shutil:
-            with mock.patch('fab.steps.root_inc_files.Path.mkdir'):
+            with mock.patch('fab.steps.root_inc_files.Path.mkdir'), \
+                 pytest.warns(UserWarning, match="_metric_send_conn not set, cannot send metrics"):
                 root_inc_files(config)
 
         mock_shutil.copy.assert_called_once_with(inc_files[0], config.build_output)
@@ -43,5 +45,7 @@ def test_name_clash(self):
 
         with pytest.raises(FileExistsError):
             with mock.patch('fab.steps.root_inc_files.shutil'):
-                with mock.patch('fab.steps.root_inc_files.Path.mkdir'):
+                with mock.patch('fab.steps.root_inc_files.Path.mkdir'), \
+                     pytest.warns(DeprecationWarning,
+                                  match="RootIncFiles is deprecated as .inc files are due to be removed."):
                     root_inc_files(config)
diff --git a/tests/unit_tests/test_tools.py b/tests/unit_tests/test_tools.py
index 8edcb437..1898ff7f 100644
--- a/tests/unit_tests/test_tools.py
+++ b/tests/unit_tests/test_tools.py
@@ -15,12 +15,14 @@ class Test_remove_managed_flags(object):
 
     def test_gfortran(self):
         flags = ['--foo', '-J', 'nope', '--bar']
-        result = remove_managed_flags('gfortran', flags)
+        with pytest.warns(UserWarning, match="removing managed flag"):
+            result = remove_managed_flags('gfortran', flags)
         assert result == ['--foo', '--bar']
 
     def test_ifort(self):
         flags = ['--foo', '-module', 'nope', '--bar']
-        result = remove_managed_flags('ifort', flags)
+        with pytest.warns(UserWarning, match="removing managed flag"):
+            result = remove_managed_flags('ifort', flags)
         assert result == ['--foo', '--bar']
 
     def test_unknown_compiler(self):