diff --git a/.github/workflows/testpackage_reader.yml b/.github/workflows/testpackage_reader.yml
new file mode 100644
index 0000000..ee7d7b1
--- /dev/null
+++ b/.github/workflows/testpackage_reader.yml
@@ -0,0 +1,47 @@
+name: Testpackage turso 
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  testpackage:
+
+    runs-on: carrington
+
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        submodules: 'recursive'
+    - name: Install python and uv
+      uses: astral-sh/setup-uv@v6
+    - name: Install packages
+      run: |
+          module load GCC/11.3.0
+          ml Python/3.10.4-GCCcore-11.3.0
+          export PY_VERSION="3.10.4"
+          uv venv -p 3.10.4 CI_env
+          . CI_env/bin/activate
+          uv pip install cmake
+          uv pip install ../analysator-backends
+          uv pip install git+https://github.com/fmihpc/analysator.git
+    - name: Import test
+      run: |
+          module load GCC/11.3.0
+          . CI_env/bin/activate
+          python -c "import vlsvrs"
+          python -c "import cpphelpers"
+          python -c "import analysator"
+    - name: Run testpackage
+      run: |
+          module load GCC/11.3.0
+          . CI_env/bin/activate
+          python ./testpackage/testpackage_vlsvread.py
+
+
+
diff --git a/build.rs b/build.rs
index ac207a8..8355537 100644
--- a/build.rs
+++ b/build.rs
@@ -3,7 +3,7 @@ use std::process::Command;
 use std::{env, path::PathBuf};
 
 fn main() {
-    // let _cpphelpers = cmake::Config::new("cpphelpers").build();
+    let _cpphelpers = cmake::Config::new("cpphelpers").build();
     let zfp_dst = cmake::Config::new("rust/external/zfp")
         .define("BUILD_SHARED_LIBS", "OFF")
         .build();
diff --git a/cpphelpers/CMakeLists.txt b/cpphelpers/CMakeLists.txt
index 3e84101..fe950be 100644
--- a/cpphelpers/CMakeLists.txt
+++ b/cpphelpers/CMakeLists.txt
@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.10)
 project(cpphelpers)
 
 # Find Python interpreter + development headers + extension suffix
-find_package(Python3 COMPONENTS Interpreter Development.Module REQUIRED)
+find_package(Python3 $ENV{PY_VERSION} EXACT COMPONENTS Interpreter Development.Module REQUIRED)
 
 # Build the extension module
 add_library(cpphelpers SHARED src/cpphelpers.cpp)
diff --git a/testpackage/bulk_hermite_compressed.0000001.vlsv b/testpackage/bulk_hermite_compressed.0000001.vlsv
new file mode 100644
index 0000000..2d5ce50
Binary files /dev/null and b/testpackage/bulk_hermite_compressed.0000001.vlsv differ
diff --git a/testpackage/testpackage_vlsvread.py b/testpackage/testpackage_vlsvread.py
new file mode 100644
index 0000000..80c7307
--- /dev/null
+++ b/testpackage/testpackage_vlsvread.py
@@ -0,0 +1,211 @@
+import analysator as pt
+import numpy as np
+import vlsvrs
+import os
+import hashlib
+import pickle
+import importlib
+
+datalocation = "/turso/group/spacephysics/analysator/CI/analysator-test-data/vlasiator/"
+files=["3D/FID/bulk1/bulk1.0000995.vlsv",
+       "3D/FHA/bulk1/bulk1.0000990.vlsv",
+]
+class Tester:
+    def __init__(self,filename=None):
+        self.filename=filename
+        self.vlsvobj=None
+        self.hashes_dict_rust={}
+        self.hashes_dict_python={}
+    def changeFile(self,filename):
+        self.filename=filename
+    def loadPickle(self,file):
+        self.pickled = pickle.load(file)
+    def dumpPickle(self,file):
+        pickle.dump(self.hashes_dict,file)
+
+    def load(self,backend=None):
+        if not backend or backend.lower()=="rust":
+            self.vlsvobj_rust=vlsvrs.VlsvFile(self.filename)
+        if not backend or backend.lower()=="python":
+            self.vlsvobj_python=pt.vlsvfile.VlsvReader(self.filename)
+
+    def setHashTarget(self,backend):
+        if backend=='rust':
+            self.vlsvobj=self.vlsvobj_rust
+        elif backend=='python':
+            self.vlsvobj=self.vlsvobj_python
+        else:
+            print("None set, give valid backend")
+
+    def hash(self,func,args,op=None,opargs=None,both=False,loop=False,flatten=True,sort=False):
+            
+        def update(vlsvobj,op,opargs,args,hashdict,loop=False):
+            #If we want to repeat same function func with different arguments
+            if loop:
+                for arg in args:
+                    print(arg,args)
+                    update(vlsvobj,op,opargs,arg,hashdict)
+                return 0
+            argkey=str(args)
+            opsname="_"+str(op)+"_"+str(opargs)
+            #Get the method of the vlsvobj that matches the given func str
+            t=getattr(vlsvobj,func)
+            #Handle arguments and call the function with the given args to get return value
+            if type(args) is dict:
+                retval=t(**args)
+            elif type(args) is list:
+                retval=t(*args)
+            else: 
+                raise IOError(f"Wrong args type: {type(args)} {args}")
+            #If we want to do operations on the retval for example reshaping, type chaning or sorting
+            if op and opargs:
+                #Make into list for handling
+                if type(op) is not list:
+                    op=[op]
+                    opargs=[opargs]
+
+                for i,f in enumerate(op):
+                    try:
+                        fun=getattr(retval,f)
+                    except AttributeError:
+                        try: 
+                            #if given function is not method of retval we make retval the argument of function
+                            if '.' in f:
+                                funcl=f.split('.')
+                                #in case it is inside a module like numpy we need to get instance of the module
+                                funcl[0]=importlib.import_module(funcl[0])
+
+                                fun=getattr(funcl[0],funcl[1])
+                            else:
+                                fun=f
+                            opargs[i]=[retval]
+                        except AttributeError as e:
+                            raise AttributeError(f"Did not find func {func} to operate with: {e}")
+                    retval=fun(*opargs[i])
+
+            #save hash of the retval as array
+            retval=np.array(retval)
+            print(retval.shape)
+            if flatten:
+                retval.reshape((-1,))
+            if sort:
+                retval.sort()
+            # print(retval)
+            # print(retval.shape)
+            # print("end")
+            if self.filename not in hashdict.keys():
+                hashdict[self.filename]={}
+                if func not in hashdict:
+                    hashdict[self.filename][func]={}
+            hashdict[self.filename][func][argkey]=[hashlib.sha256(retval.tobytes()).hexdigest(),opsname]
+            # if vlsvobj==self.vlsvobj_rust:
+            #     if self.filename not in self.hashes_dict_rust.keys():
+            #         self.hashes_dict_rust[self.filename]={}
+            #         if func not in self.hashes_dict_rust:
+            #             self.hashes_dict_rust[self.filename][func]={}
+            #     self.hashes_dict_rust[self.filename][func][argkey]=[hashlib.sha256(retval.tobytes()).hexdigest(),opsname]
+            # elif vlsvobj==self.vlsvobj_python:
+            #     if self.filename not in self.hashes_dict_python.keys():
+            #         self.hashes_dict_python[self.filename]={}
+            #         if func not in self.hashes_dict_python:
+            #             self.hashes_dict_python[self.filename][func]={}
+            #     self.hashes_dict_python[self.filename][func][argkey]=[hashlib.sha256(retval.tobytes()).hexdigest(),opsname]
+        if not both:
+            if self.vlsvobj==self.vlsvobj_python:
+                hashdict=self.hashes_dict_python
+            elif self.vlsvobj==self.vlsvobj_rust:
+                hashdict=self.hashes_dict_rust
+            update(self.vlsvobj,op,opargs,args,hashdict,loop)
+        else:
+            update(self.vlsvobj_rust,op,opargs,args,self.hashes_dict_rust,loop)
+            update(self.vlsvobj_python,op,opargs,args,self.hashes_dict_python,loop)
+
+    def compare(self,funcpy,argspy,funcrust,argsrust):
+        try:
+            py=getattr(self.vlsvobj_python,funcpy)
+            retval_py=py(**argspy)
+
+            rust=getattr(self.vlsvobj_rust,funcrust)
+            retval_rust=rust(**argsrust)
+
+        except Exception as e:
+            raise e
+
+        if type(retval_py) is dict and type(retval_rust) is dict :
+            stack=list(retval_rust.keys())
+            if (len(retval_py)!=len(retval_rust)) and len(list(retval_py.keys()))!=0:
+                raise SystemError("one or both of the dictionaries returned by the readers are empty")
+            for key in retval_py.keys():
+                if retval_rust[key] == retval_py[key]:
+                    stack.remove(key) #maybe a some ohter way to remove it is faster? 
+                else:
+                    raise SystemError("returned dictionary values between vlsvreader and vlsvrs do not match")
+            if len(stack)!=0:
+                raise KeyError("returned dictionry from vlsvrs contains keys not present in dictonary returned by python.") 
+            return True
+        else:
+            raise NotImplementedError 
+        
+
+#read ref from file
+#(Cellid as variable) reading single cellid ,reading cellid list, (input and output cellid should be same assertion).
+#vector (tensor variables from datareduction), read_variable, cellid 0 is nonexistant, error check.
+#some datareduction
+#read_vdf() (vlsvrs)
+# read_variable, compare against fsgird, vg 
+# read_velocitycells (vlsvreader)
+
+# read_vdf_spares 
+# 
+ciTester = Tester()
+# files=["s"]
+for file in files:
+
+    #Load data 
+    filename=os.path.join(datalocation,file)
+
+    # filename="/home/siclasse/bulk.0000110.vlsv"
+    #filename="/home/siclasse/Downloads/bulk_hermite_compressed.0000001.vlsv"
+    ciTester.changeFile(filename)
+    ciTester.load()
+
+    #Test compare
+    cid=ciTester.vlsvobj_python.get_cellid_with_vdf(np.array([0,0,0]))
+    ciTester.compare("read_velocity_cells",{"cellid":cid,"pop":"proton"},"read_vdf_sparse",{"cid":cid,"pop":"proton"})
+    
+    
+    #Make hash python
+    ciTester.setHashTarget("rust")
+    #ciTester.hash("read_variable",{"variable":"CellID","op":0},op=["reshape","astype","numpy.sort"],opargs=[[tuple([-1])],[int],[]],sort=False,flatten=False)
+    variables_to_test=["CellID","vg_rhom","vg_v","vg_rhoq","proton/vg_rho","proton/vg_v"] #fg_variable read issue with read_variable
+    variables_to_test_nonraw=["fg_b","fg_v"]
+    pylist=ciTester.vlsvobj_python.get_variables()
+    rustlist=ciTester.vlsvobj_rust.list_variables()
+    variables=[[var] for var in variables_to_test if (var in pylist and var in rustlist)] 
+    nonraw_vars=[[var,0] for var in variables_to_test_nonraw if (var in pylist and var in rustlist)] 
+    ciTester.hash("read_variable_raw",variables,loop=True)
+    ciTester.hash("read_variable",nonraw_vars,loop=True)
+
+    #Make hash python
+    ciTester.setHashTarget("python")
+    variables.extend([[var[0]] for var in nonraw_vars]) #prob some prettier way than looping through it all but it's not a big list
+    ciTester.hash("read_variable",variables,loop=True)
+     
+
+print(ciTester.hashes_dict_python)
+print(ciTester.hashes_dict_rust)
+key_map_rust_to_py={"read_variable_raw":"read_variable","read_variable":"read_variable"}
+for file in ciTester.hashes_dict_rust.keys():
+    print(f"------{file}------")
+    for key in ciTester.hashes_dict_rust[file].keys():
+        py_dict=ciTester.hashes_dict_python[file][key_map_rust_to_py[key]]
+        rust_dict=ciTester.hashes_dict_rust[file][key]
+        for argcall in rust_dict.keys():
+            if rust_dict[argcall][0]!=py_dict[argcall][0]:
+                print(rust_dict[argcall][0],py_dict[argcall][0])
+                print("Not match")
+            else:
+                print("debug", argcall, rust_dict[argcall][0])
+
+    
+