diff --git a/TODO.md b/TODO.md
index 73eb659..5e7ea5f 100644
--- a/TODO.md
+++ b/TODO.md
@@ -7,9 +7,10 @@
 - [x] add github action
 - [x] add pub to pypi
 
-## next
+## v0.2.0
 
 - [ ] add fmi3 support
-- [ ] add more tests
-- [ ] add reference fmu download use reference fmu for testing
+- [x] add more tests
+- [x] add reference fmu download use reference fmu for testing
 - [ ] add cli tool
+- [ ] add to_xml function
diff --git a/tests/samples/fmi2/test1.xml b/tests/samples/fmi2/test1.xml
deleted file mode 100644
index 187811e..0000000
--- a/tests/samples/fmi2/test1.xml
+++ /dev/null
@@ -1,105 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<fmiModelDescription
-  fmiVersion="2.0"
-  modelName="BouncingBall"
-  description="This model calculates the trajectory, over time, of a ball dropped from a height of 1 m"
-  generationTool="Reference FMUs (v0.0.39)"
-  generationDateAndTime="2025-06-12T19:14:13.998312+00:00"
-  guid="{1AE5E10D-9521-4DE3-80B9-D0EAAA7D5AF1}"
-  numberOfEventIndicators="1">
-
-  <ModelExchange
-    modelIdentifier="BouncingBall"
-    canNotUseMemoryManagementFunctions="true"
-    canGetAndSetFMUstate="true"
-    canSerializeFMUstate="true">
-    <SourceFiles>
-      <File name="all.c"/>
-    </SourceFiles>
-  </ModelExchange>
-
-  <CoSimulation
-    modelIdentifier="BouncingBall"
-    canHandleVariableCommunicationStepSize="true"
-    canNotUseMemoryManagementFunctions="true"
-    canGetAndSetFMUstate="true"
-    canSerializeFMUstate="true">
-    <SourceFiles>
-      <File name="all.c"/>
-    </SourceFiles>
-  </CoSimulation>
-
-  <UnitDefinitions>
-    <Unit name="m">
-      <BaseUnit m="1"/>
-    </Unit>
-    <Unit name="m/s">
-      <BaseUnit m="1" s="-1"/>
-    </Unit>
-    <Unit name="m/s2">
-      <BaseUnit m="1" s="-2"/>
-    </Unit>
-  </UnitDefinitions>
-
-  <TypeDefinitions>
-    <SimpleType name="Position">
-      <Real quantity="Position" unit="m"/>
-    </SimpleType>
-    <SimpleType name="Velocity">
-      <Real quantity="Velocity" unit="m/s"/>
-    </SimpleType>
-    <SimpleType name="Acceleration">
-      <Real quantity="Acceleration" unit="m/s2"/>
-    </SimpleType>
-  </TypeDefinitions>
-
-  <LogCategories>
-    <Category name="logEvents" description="Log events"/>
-    <Category name="logStatusError" description="Log error messages"/>
-  </LogCategories>
-
-  <DefaultExperiment startTime="0" stopTime="3" stepSize="1e-2"/>
-
-  <ModelVariables>
-    <ScalarVariable name="time" valueReference="0" causality="independent" variability="continuous" description="Simulation time">
-      <Real/>
-    </ScalarVariable>
-    <ScalarVariable name="h" valueReference="1" causality="output" variability="continuous" initial="exact" description="Position of the ball">
-      <Real start="1" reinit="true" declaredType="Position"/>
-    </ScalarVariable>
-    <ScalarVariable name="der(h)" valueReference="2" causality="local" variability="continuous" initial="calculated" description="Derivative of h">
-      <Real derivative="2" declaredType="Velocity"/>
-    </ScalarVariable>
-    <ScalarVariable name="v" valueReference="3" causality="output" variability="continuous" initial="exact" description="Velocity of the ball">
-      <Real start="0" reinit="true" declaredType="Velocity"/>
-    </ScalarVariable>
-    <ScalarVariable name="der(v)" valueReference="4" causality="local" variability="continuous" initial="calculated" description="Derivative of v">
-      <Real derivative="4" declaredType="Acceleration"/>
-    </ScalarVariable>
-    <ScalarVariable name="g" valueReference="5" causality="parameter" variability="fixed" initial="exact" description="Gravity acting on the ball">
-      <Real start="-9.81" declaredType="Acceleration"/>
-    </ScalarVariable>
-    <ScalarVariable name="e" valueReference="6" causality="parameter" variability="tunable" initial="exact" description="Coefficient of restitution">
-      <Real start="0.7" min="0.5" max="1"/>
-    </ScalarVariable>
-    <ScalarVariable name="v_min" valueReference="7" variability="constant" description="Velocity below which the ball stops bouncing">
-      <Real start="0.1" declaredType="Velocity"/>
-    </ScalarVariable>
-  </ModelVariables>
-
-  <ModelStructure>
-    <Outputs>
-      <Unknown index="2" dependencies=""/>
-      <Unknown index="4" dependencies=""/>
-    </Outputs>
-    <Derivatives>
-      <Unknown index="3" dependencies="4" dependenciesKind="constant"/>
-      <Unknown index="5" dependencies="6" dependenciesKind="constant"/>
-    </Derivatives>
-    <InitialUnknowns>
-      <Unknown index="3" dependencies="4" dependenciesKind="constant"/>
-      <Unknown index="5" dependencies="6" dependenciesKind="constant"/>
-    </InitialUnknowns>
-  </ModelStructure>
-
-</fmiModelDescription>
diff --git a/tests/samples/fmi2/test2.xml b/tests/samples/fmi2/test2.xml
deleted file mode 100644
index 1587420..0000000
--- a/tests/samples/fmi2/test2.xml
+++ /dev/null
@@ -1,115 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<fmiModelDescription
-  fmiVersion="2.0"
-  modelName="Feedthrough"
-  description="A model to test different variable types, causalities, and variabilities"
-  generationTool="Reference FMUs (v0.0.39)"
-  generationDateAndTime="2025-06-12T19:14:14.505874+00:00"
-  guid="{37B954F1-CC86-4D8F-B97F-C7C36F6670D2}"
-  numberOfEventIndicators="0">
-
-  <ModelExchange
-    modelIdentifier="Feedthrough"
-    canNotUseMemoryManagementFunctions="true"
-    canGetAndSetFMUstate="true"
-    canSerializeFMUstate="true">
-    <SourceFiles>
-      <File name="all.c"/>
-    </SourceFiles>
-  </ModelExchange>
-
-  <CoSimulation
-    modelIdentifier="Feedthrough"
-    canHandleVariableCommunicationStepSize="true"
-    canNotUseMemoryManagementFunctions="true"
-    canGetAndSetFMUstate="true"
-    canSerializeFMUstate="true">
-    <SourceFiles>
-      <File name="all.c"/>
-    </SourceFiles>
-  </CoSimulation>
-
-  <TypeDefinitions>
-    <SimpleType name="Option">
-      <Enumeration>
-        <Item name="Option 1" value="1" description="First option"/>
-        <Item name="Option 2" value="2" description="Second option"/>
-      </Enumeration>
-    </SimpleType>
-  </TypeDefinitions>
-
-  <LogCategories>
-    <Category name="logEvents" description="Log events"/>
-    <Category name="logStatusError" description="Log error messages"/>
-  </LogCategories>
-
-  <DefaultExperiment stopTime="2"/>
-
-  <ModelVariables>
-    <ScalarVariable name="time" valueReference="0" causality="independent" variability="continuous">
-      <Real/>
-    </ScalarVariable>
-    <ScalarVariable name="Float64_fixed_parameter" valueReference="5" causality="parameter" variability="fixed">
-      <Real start="0"/>
-    </ScalarVariable>
-    <ScalarVariable name="Float64_tunable_parameter" valueReference="6" causality="parameter" variability="tunable">
-      <Real start="0"/>
-    </ScalarVariable>
-    <ScalarVariable name="Float64_continuous_input" valueReference="7" causality="input">
-      <Real start="0"/>
-    </ScalarVariable>
-    <ScalarVariable name="Float64_continuous_output" valueReference="8" causality="output" initial="calculated">
-      <Real/>
-    </ScalarVariable>
-    <ScalarVariable name="Float64_discrete_input" valueReference="9" causality="input" variability="discrete">
-      <Real start="0"/>
-    </ScalarVariable>
-    <ScalarVariable name="Float64_discrete_output" valueReference="10" causality="output" variability="discrete" initial="calculated">
-      <Real/>
-    </ScalarVariable>
-    <ScalarVariable name="Int32_input" valueReference="19" causality="input" variability="discrete">
-      <Integer start="0"/>
-    </ScalarVariable>
-    <ScalarVariable name="Int32_output" valueReference="20" causality="output" variability="discrete" initial="calculated">
-      <Integer/>
-    </ScalarVariable>
-    <ScalarVariable name="Boolean_input" valueReference="27" causality="input" variability="discrete">
-      <Boolean start="false"/>
-    </ScalarVariable>
-    <ScalarVariable name="Boolean_output" valueReference="28" causality="output" variability="discrete" initial="calculated">
-      <Boolean/>
-    </ScalarVariable>
-    <ScalarVariable name="String_input" valueReference="29" causality="input" variability="discrete">
-        <String start="Set me!"/>
-    </ScalarVariable>
-    <ScalarVariable name="String_output" valueReference="30" causality="output" variability="discrete">
-        <String/>
-    </ScalarVariable>
-    <ScalarVariable name="Enumeration_input" valueReference="33" causality="input" variability="discrete">
-      <Enumeration declaredType="Option" start="1"/>
-    </ScalarVariable>
-    <ScalarVariable name="Enumeration_output" valueReference="34" causality="output" variability="discrete" initial="calculated">
-      <Enumeration declaredType="Option"/>
-    </ScalarVariable>
-  </ModelVariables>
-
-  <ModelStructure>
-    <Outputs>
-      <Unknown index="5" dependencies="2 3 4" dependenciesKind="constant constant constant"/>
-      <Unknown index="7" dependencies="6" dependenciesKind="constant"/>
-      <Unknown index="9" dependencies="8" dependenciesKind="constant"/>
-      <Unknown index="11" dependencies="10 12" dependenciesKind="constant"/>
-      <Unknown index="13" dependencies="12" dependenciesKind="constant"/>
-      <Unknown index="15" dependencies="14" dependenciesKind="constant"/>
-    </Outputs>
-    <InitialUnknowns>
-      <Unknown index="5" dependencies="2 3 4" dependenciesKind="constant constant constant"/>
-      <Unknown index="7" dependencies="6" dependenciesKind="constant"/>
-      <Unknown index="9" dependencies="8" dependenciesKind="constant"/>
-      <Unknown index="11" dependencies="10 12" dependenciesKind="constant"/>
-      <Unknown index="13" dependencies="12" dependenciesKind="constant"/>
-      <Unknown index="15" dependencies="14" dependenciesKind="constant"/>
-    </InitialUnknowns>
-  </ModelStructure>
-
-</fmiModelDescription>
diff --git a/tests/samples/fmi2/test3.xml b/tests/samples/fmi2/test3.xml
deleted file mode 100644
index f8af862..0000000
--- a/tests/samples/fmi2/test3.xml
+++ /dev/null
@@ -1,54 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<fmiModelDescription
-  fmiVersion="2.0"
-  modelName="Stair"
-  description="This model generates a stair signal using time events"
-  generationTool="Reference FMUs (v0.0.39)"
-  generationDateAndTime="2025-06-12T19:14:14.114727+00:00"
-  guid="{BD403596-3166-4232-ABC2-132BDF73E644}"
-  numberOfEventIndicators="0">
-
-  <ModelExchange
-    modelIdentifier="Stair"
-    canNotUseMemoryManagementFunctions="true"
-    canGetAndSetFMUstate="true"
-    canSerializeFMUstate="true">
-    <SourceFiles>
-      <File name="all.c"/>
-    </SourceFiles>
-  </ModelExchange>
-
-  <CoSimulation
-    modelIdentifier="Stair"
-    canHandleVariableCommunicationStepSize="true"
-    canNotUseMemoryManagementFunctions="true"
-    canGetAndSetFMUstate="true"
-    canSerializeFMUstate="true">
-    <SourceFiles>
-      <File name="all.c"/>
-    </SourceFiles>
-  </CoSimulation>
-
-  <LogCategories>
-    <Category name="logEvents" description="Log events"/>
-    <Category name="logStatusError" description="Log error messages"/>
-  </LogCategories>
-
-  <DefaultExperiment startTime="0" stopTime="10" stepSize="0.2"/>
-
-  <ModelVariables>
-    <ScalarVariable name="time" valueReference="0" causality="independent" variability="continuous" description="Simulation time">
-      <Real/>
-    </ScalarVariable>
-    <ScalarVariable name="counter" valueReference="1" description="counts the seconds" causality="output" variability="discrete" initial="exact">
-      <Integer start="1" max="10"/>
-    </ScalarVariable>
-  </ModelVariables>
-
-  <ModelStructure>
-    <Outputs>
-      <Unknown index="2"/>
-    </Outputs>
-  </ModelStructure>
-
-</fmiModelDescription>
diff --git a/tests/samples/fmi2/test4.xml b/tests/samples/fmi2/test4.xml
deleted file mode 100644
index 996691e..0000000
--- a/tests/samples/fmi2/test4.xml
+++ /dev/null
@@ -1,66 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<fmiModelDescription
-  fmiVersion="2.0"
-  modelName="Dahlquist"
-  description="This model implements the Dahlquist test equation"
-  generationTool="Reference FMUs (v0.0.39)"
-  generationDateAndTime="2025-06-12T19:14:14.597366+00:00"
-  guid="{221063D2-EF4A-45FE-B954-B5BFEEA9A59B}"
-  numberOfEventIndicators="0">
-
-  <ModelExchange
-    modelIdentifier="Dahlquist"
-    canNotUseMemoryManagementFunctions="true"
-    canGetAndSetFMUstate="true"
-    canSerializeFMUstate="true">
-    <SourceFiles>
-      <File name="all.c"/>
-    </SourceFiles>
-  </ModelExchange>
-
-  <CoSimulation
-    modelIdentifier="Dahlquist"
-    canHandleVariableCommunicationStepSize="true"
-    canNotUseMemoryManagementFunctions="true"
-    canGetAndSetFMUstate="true"
-    canSerializeFMUstate="true">
-    <SourceFiles>
-      <File name="all.c"/>
-    </SourceFiles>
-  </CoSimulation>
-
-  <LogCategories>
-    <Category name="logEvents" description="Log events"/>
-    <Category name="logStatusError" description="Log error messages"/>
-  </LogCategories>
-
-  <DefaultExperiment startTime="0" stopTime="10" stepSize="0.1"/>
-
-  <ModelVariables>
-    <ScalarVariable name="time" valueReference="0" causality="independent" variability="continuous" description="Simulation time">
-      <Real/>
-    </ScalarVariable>
-    <ScalarVariable name="x" valueReference="1" description="the only state" causality="output" variability="continuous" initial="exact">
-      <Real start="1"/>
-    </ScalarVariable>
-    <ScalarVariable name="der(x)" valueReference="2" causality="local" variability="continuous" initial="calculated">
-      <Real derivative="2"/>
-    </ScalarVariable>
-    <ScalarVariable name="k" valueReference="3" causality="parameter" variability="fixed" initial="exact">
-      <Real start="1"/>
-    </ScalarVariable>
-  </ModelVariables>
-
-  <ModelStructure>
-    <Outputs>
-      <Unknown index="2" dependencies=""/>
-    </Outputs>
-    <Derivatives>
-      <Unknown index="3" dependencies="2" dependenciesKind="fixed"/>
-    </Derivatives>
-    <InitialUnknowns>
-      <Unknown index="3" dependencies="2 4" dependenciesKind="dependent dependent"/>
-    </InitialUnknowns>
-  </ModelStructure>
-
-</fmiModelDescription>