diff --git a/tests/test_components/test_offset_converter.py b/tests/test_components/test_offset_converter.py
index f329c882c..7553faa85 100644
--- a/tests/test_components/test_offset_converter.py
+++ b/tests/test_components/test_offset_converter.py
@@ -2,6 +2,7 @@
 
 import numpy as np
 import pytest
+from oemof.tools.debugging import ExperimentalFeatureWarning
 
 from oemof import solph
 from oemof.solph._plumbing import sequence
@@ -104,58 +105,67 @@ def check_results(
 def add_OffsetConverter(
     es, reference_bus, nominal_value, minimal_value, eta_at_nom, eta_at_min
 ):
+    # Use of experimental API to access nodes by label.
+    # Can be removed with future release of network.
+    with warnings.catch_warnings(
+        action="ignore", category=ExperimentalFeatureWarning
+    ):
+        oc_inputs = {
+            b: solph.Flow()
+            for label, b in es.node.items()
+            if "bus input" in label
+        }
+        oc_outputs = {
+            b: solph.Flow()
+            for label, b in es.node.items()
+            if "bus output" in label
+        }
+
+        if reference_bus in oc_outputs:
+            f = oc_outputs[reference_bus]
+            get_slope_and_offset = slope_offset_from_nonconvex_output
+            fix = [0] + np.linspace(minimal_value, nominal_value, 9).tolist()
+        else:
+            f = oc_inputs[reference_bus]
+            get_slope_and_offset = slope_offset_from_nonconvex_input
+            fix = [0] + np.linspace(
+                minimal_value * eta_at_min[es.node["bus output 0"]],
+                nominal_value * eta_at_nom[es.node["bus output 0"]],
+                9,
+            ).tolist()
+
+        fix_flow = es.flows()[es.node["bus output 0"], es.node["sink 0"]]
+        fix_flow.fix = fix
+        fix_flow.nominal_value = 1
+
+        slopes = {}
+        offsets = {}
+
+        for bus in list(oc_inputs) + list(oc_outputs):
+            if bus == reference_bus:
+                continue
+            slope, offset = get_slope_and_offset(
+                1,
+                minimal_value / nominal_value,
+                eta_at_nom[bus],
+                eta_at_min[bus],
+            )
+            slopes[bus] = slope
+            offsets[bus] = offset
 
-    oc_inputs = {
-        b: solph.Flow() for label, b in es.node.items() if "bus input" in label
-    }
-    oc_outputs = {
-        b: solph.Flow()
-        for label, b in es.node.items()
-        if "bus output" in label
-    }
+        f.nonconvex = solph.NonConvex()
+        f.nominal_value = nominal_value
+        f.min = sequence(minimal_value / nominal_value)
 
-    if reference_bus in oc_outputs:
-        f = oc_outputs[reference_bus]
-        get_slope_and_offset = slope_offset_from_nonconvex_output
-        fix = [0] + np.linspace(minimal_value, nominal_value, 9).tolist()
-    else:
-        f = oc_inputs[reference_bus]
-        get_slope_and_offset = slope_offset_from_nonconvex_input
-        fix = [0] + np.linspace(
-            minimal_value * eta_at_min[es.node["bus output 0"]],
-            nominal_value * eta_at_nom[es.node["bus output 0"]],
-            9,
-        ).tolist()
-
-    fix_flow = es.flows()[es.node["bus output 0"], es.node["sink 0"]]
-    fix_flow.fix = fix
-    fix_flow.nominal_value = 1
-
-    slopes = {}
-    offsets = {}
-
-    for bus in list(oc_inputs) + list(oc_outputs):
-        if bus == reference_bus:
-            continue
-        slope, offset = get_slope_and_offset(
-            1, minimal_value / nominal_value, eta_at_nom[bus], eta_at_min[bus]
+        oc = solph.components.OffsetConverter(
+            label="offset converter",
+            inputs=oc_inputs,
+            outputs=oc_outputs,
+            conversion_factors=slopes,
+            normed_offsets=offsets,
         )
-        slopes[bus] = slope
-        offsets[bus] = offset
-
-    f.nonconvex = solph.NonConvex()
-    f.nominal_value = nominal_value
-    f.min = sequence(minimal_value / nominal_value)
-
-    oc = solph.components.OffsetConverter(
-        label="offset converter",
-        inputs=oc_inputs,
-        outputs=oc_outputs,
-        conversion_factors=slopes,
-        normed_offsets=offsets,
-    )
 
-    es.add(oc)
+        es.add(oc)
 
 
 def test_custom_properties():
@@ -476,8 +486,13 @@ def test_two_OffsetConverters_with_and_without_investment():
 
     es.add(oc)
 
-    fix_flow = es.flows()[es.node["bus output 0"], es.node["sink 0"]]
-    fix_flow.fix = [v * 2 for v in fix_flow.fix]
+    # Use of experimental API to access nodes by label.
+    # Can be removed with future release of network.
+    with warnings.catch_warnings(
+        action="ignore", category=ExperimentalFeatureWarning
+    ):
+        fix_flow = es.flows()[es.node["bus output 0"], es.node["sink 0"]]
+        fix_flow.fix = [v * 2 for v in fix_flow.fix]
     # if the model solves it is feasible
     _ = solve_and_extract_results(es)
 
@@ -491,10 +506,15 @@ def test_OffsetConverter_05x_compatibility():
     nominal_value = 10
     minimal_value = 3
 
-    fix = [0] + np.linspace(minimal_value, nominal_value, 9).tolist()
-    fix_flow = es.flows()[es.node["bus output 0"], es.node["sink 0"]]
-    fix_flow.fix = fix
-    fix_flow.nominal_value = 1
+    # Use of experimental API to access nodes by label.
+    # Can be removed with future release of network.
+    with warnings.catch_warnings(
+        action="ignore", category=ExperimentalFeatureWarning
+    ):
+        fix = [0] + np.linspace(minimal_value, nominal_value, 9).tolist()
+        fix_flow = es.flows()[es.node["bus output 0"], es.node["sink 0"]]
+        fix_flow.fix = fix
+        fix_flow.nominal_value = 1
 
     eta_at_nom = 0.7
     eta_at_min = 0.5
diff --git a/tests/test_components/test_sink.py b/tests/test_components/test_sink.py
index 97622a181..00f891ffb 100644
--- a/tests/test_components/test_sink.py
+++ b/tests/test_components/test_sink.py
@@ -1,6 +1,8 @@
 # -*- coding: utf-8 -*-
+import warnings
 
 import pytest
+from oemof.tools.debugging import ExperimentalFeatureWarning
 
 from oemof import solph
 
@@ -22,18 +24,22 @@ def test_multi_input_sink():
         es.add(
             solph.components.Source(f"source {i}", outputs={b: solph.Flow()})
         )
-
-    es.add(
-        solph.components.Sink(
-            inputs={
-                es.node[f"bus input {i}"]: solph.Flow(
-                    nominal_value=1,
-                    variable_costs=costs,
-                )
-                for i in range(num_in)
-            }
+    # Use of experimental API to access nodes by label.
+    # Can be removed with future release of network.
+    with warnings.catch_warnings(
+        action="ignore", category=ExperimentalFeatureWarning
+    ):
+        es.add(
+            solph.components.Sink(
+                inputs={
+                    es.node[f"bus input {i}"]: solph.Flow(
+                        nominal_value=1,
+                        variable_costs=costs,
+                    )
+                    for i in range(num_in)
+                }
+            )
         )
-    )
 
     model = solph.Model(es)
     model.solve("cbc")
diff --git a/tests/test_components/test_source.py b/tests/test_components/test_source.py
index 16fa294fb..f54977a76 100644
--- a/tests/test_components/test_source.py
+++ b/tests/test_components/test_source.py
@@ -1,6 +1,8 @@
 # -*- coding: utf-8 -*-
+import warnings
 
 import pytest
+from oemof.tools.debugging import ExperimentalFeatureWarning
 
 from oemof import solph
 
@@ -21,17 +23,22 @@ def test_multi_output_source():
         es.add(b)
         es.add(solph.components.Sink(f"source {i}", inputs={b: solph.Flow()}))
 
-    es.add(
-        solph.components.Source(
-            outputs={
-                es.node[f"bus input {i}"]: solph.Flow(
-                    nominal_value=1,
-                    variable_costs=costs,
-                )
-                for i in range(num_out)
-            }
+    # Use of experimental API to access nodes by label.
+    # Can be removed with future release of network.
+    with warnings.catch_warnings(
+        action="ignore", category=ExperimentalFeatureWarning
+    ):
+        es.add(
+            solph.components.Source(
+                outputs={
+                    es.node[f"bus input {i}"]: solph.Flow(
+                        nominal_value=1,
+                        variable_costs=costs,
+                    )
+                    for i in range(num_out)
+                }
+            )
         )
-    )
 
     model = solph.Model(es)
     model.solve("cbc")
diff --git a/tests/test_solph_network_classes.py b/tests/test_solph_network_classes.py
index 46f032da1..35d421d87 100644
--- a/tests/test_solph_network_classes.py
+++ b/tests/test_solph_network_classes.py
@@ -12,6 +12,7 @@
 import warnings
 
 import pytest
+from oemof.tools.debugging import SuspiciousUsageWarning
 
 from oemof import solph
 
@@ -60,20 +61,22 @@ def test_sequence_conversion_factor_from_list_wrong_length(self):
         with pytest.raises(IndexError):
             self.a = transf.conversion_factors[self.bus][6]
 
-    @pytest.mark.filterwarnings("ignore:Attribute <outputs>:UserWarning")
     def test_converter_missing_output_create_empty_dict(self):
-        trfr = solph.components.Converter(inputs={})
-        assert trfr.outputs == {}
+        with pytest.warns(SuspiciousUsageWarning):
+            trfr = solph.components.Converter(inputs={})
+            assert trfr.outputs == {}
 
-    @pytest.mark.filterwarnings("ignore:Attribute <inputs>:UserWarning")
     def test_converter_missing_input_create_empty_dict(self):
-        trfr = solph.components.Converter(outputs={})
-        assert trfr.inputs == {}
+        with pytest.warns(SuspiciousUsageWarning):
+            trfr = solph.components.Converter(outputs={})
+            assert trfr.inputs == {}
 
 
 def test_transformer_wrapper():
     with pytest.warns(FutureWarning):
-        solph.components.Transformer()
+        # no inputs/outputs
+        with pytest.warns(SuspiciousUsageWarning):
+            solph.components.Transformer()
 
 
 def test_offset_transformer_wrapper():