diff --git a/.travis.yml b/.travis.yml
index 747f953..6ba124f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,17 +1,25 @@
 language: python
 python:
 - '3.6.5'
+- '3.5'
+- '3.6'
+- '3.7'
+- '3.8'
 before_install:
+- python --version
+- pip install -U pip
+- pip install -U pytest
 - pip install codecov
 - pip install coverage
+- pip install pytest-cov
 
 install:
 - pip install -r requirements.txt
 - pip install wheel
+- python setup.py bdist_wheel
 
 script:
-- python setup.py bdist_wheel
-- coverage run tests/tests_tools.py
+- pytest --cov-report term --cov=investpy gklearn/tests/
 
 after_success:
 - codecov
diff --git a/gklearn/tests/__init__.py b/gklearn/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/gklearn/tests/requirements.txt b/gklearn/tests/requirements.txt
new file mode 100644
index 0000000..a48620b
--- /dev/null
+++ b/gklearn/tests/requirements.txt
@@ -0,0 +1,7 @@
+numpy==1.15.2
+scipy==1.1.0
+matplotlib==3.0.0
+networkx==2.2
+scikit-learn==0.20.0
+tabulate==0.8.2
+tqdm==4.26.0
diff --git a/gklearn/tests/tests_graphkernels.py b/gklearn/tests/tests_graphkernels.py
new file mode 100644
index 0000000..7154972
--- /dev/null
+++ b/gklearn/tests/tests_graphkernels.py
@@ -0,0 +1,32 @@
+"""Tests of graph kernels.
+"""
+
+#import pytest
+from gklearn.utils.graphfiles import loadDataset
+
+
+def test_spkernel():
+    """Test shortest path kernel.
+    """
+    from gklearn.kernels.spKernel import spkernel
+    from gklearn.utils.kernels import deltakernel, gaussiankernel, kernelproduct
+    import functools
+    import multiprocessing
+
+    ds_file = '../../datasets/Alkane/dataset.ds'
+    ds_y = '../../datasets/Alkane/dataset_boiling_point_names.txt'
+    Gn, y = loadDataset(ds_file, filename_y=ds_y)
+    Gn = Gn[0:10]
+    y = y[0:10]
+    
+    mixkernel = functools.partial(kernelproduct, deltakernel, gaussiankernel)
+    try:
+        Kmatrix, run_time, idx = spkernel(Gn, node_label=None, node_kernels=
+            {'symb': deltakernel, 'nsymb': gaussiankernel, 'mix': mixkernel},
+            n_jobs=multiprocessing.cpu_count(), verbose=True)
+    except Exception as exception:
+        assert False, exception
+    
+
+if __name__ == "__main__":
+    test_spkernel()
\ No newline at end of file
diff --git a/tests/tests_tools.py b/gklearn/tests/tests_tools.py
similarity index 100%
rename from tests/tests_tools.py
rename to gklearn/tests/tests_tools.py