--- a
+++ b/tests/test_sequences.py
@@ -0,0 +1,103 @@
+import dask.dataframe as dd
+
+from openomics.database.sequence import GENCODE, MirBase
+from .test_multiomics import *
+
+
+@pytest.fixture
+def generate_GENCODE():
+    gencode = GENCODE(path="ftp://ftp.ebi.ac.uk/pub/databases/gencode/Gencode_human/release_32/",
+                      file_resources={"long_noncoding_RNAs.gtf": "gencode.v32.long_noncoding_RNAs.gtf.gz",
+                                      "lncRNA_transcripts.fa": "gencode.v32.lncRNA_transcripts.fa.gz"}, )
+
+    gencode.data = gencode.data.sample(frac=0.01)
+    return gencode
+
+
+@pytest.fixture
+def generate_GENCODE_dask():
+    gencode = GENCODE(path="ftp://ftp.ebi.ac.uk/pub/databases/gencode/Gencode_human/release_32/",
+                      file_resources={"long_noncoding_RNAs.gtf": "gencode.v32.long_noncoding_RNAs.gtf.gz",
+                                      "lncRNA_transcripts.fa": "gencode.v32.lncRNA_transcripts.fa.gz"},
+                      blocksize='10MB')
+
+    gencode.data = gencode.data.sample(frac=0.01)
+    return gencode
+
+
+@pytest.fixture
+def generate_MirBase_ftp():
+    mirbase = MirBase(path="ftp://mirbase.org/pub/mirbase/CURRENT/")
+    mirbase.data = mirbase.data.sample(frac=0.01)
+    return mirbase
+
+
+def test_import_mirbase_db(generate_MirBase_ftp):
+    """
+    Args:
+        generate_MirBase_ftp:
+    """
+    assert generate_MirBase_ftp.data_path == "ftp://mirbase.org/pub/mirbase/CURRENT/"
+
+
+def test_import_GENCODE(generate_GENCODE):
+    """
+    Args:
+        generate_GENCODE:
+    """
+    assert generate_GENCODE.data_path == 'ftp://ftp.ebi.ac.uk/pub/databases/gencode/Gencode_human/release_32/'
+
+
+def test_import_dask_GENCODE(generate_GENCODE_dask):
+    assert isinstance(generate_GENCODE_dask.data, dd.DataFrame)
+
+
+def test_annotate_GENCODE(generate_TCGA_LUAD, generate_GENCODE):
+    """
+    Args:
+        generate_TCGA_LUAD:
+        generate_GENCODE:
+    """
+    generate_TCGA_LUAD.LncRNA.annotate_attributes(generate_GENCODE, on="gene_id", columns=['gene_name'])
+
+    # Test join on off-index
+    generate_TCGA_LUAD.LncRNA.annotate_attributes(generate_GENCODE,
+                                                  on="gene_name",
+                                                  columns=['transcript_id'],
+                                                  agg="concat")
+
+    assert {'gene_name', 'transcript_id'}.issubset(
+        generate_TCGA_LUAD.LncRNA.annotations.columns)
+
+
+def test_annotate_dask_GENCODE(generate_TCGA_LUAD, generate_GENCODE_dask):
+    """
+    Args:
+        generate_TCGA_LUAD:
+        generate_GENCODE_dask:
+    """
+    generate_GENCODE_dask.data = generate_GENCODE_dask.data[generate_GENCODE_dask.data["gene_id"].notnull()]
+
+    # Test join on index column
+    generate_TCGA_LUAD.LncRNA.annotate_attributes(generate_GENCODE_dask,
+                                                  on="gene_id",
+                                                  columns=['gene_name'],
+                                                  agg="concat")
+
+    # Test join on off-index
+    generate_TCGA_LUAD.LncRNA.annotate_attributes(generate_GENCODE_dask,
+                                                  on="gene_name",
+                                                  columns=['transcript_id'],
+                                                  agg="concat")
+
+    assert {'gene_name', 'transcript_id'}.issubset(
+        generate_TCGA_LUAD.LncRNA.annotations.columns)
+
+
+def test_annotate_sequence_GENCODE(generate_TCGA_LUAD, generate_GENCODE):
+    generate_TCGA_LUAD.LncRNA.annotate_sequences(generate_GENCODE,
+                                                 on="gene_id",
+                                                 omic="LncRNA",
+                                                 agg="longest")
+
+    assert not generate_TCGA_LUAD.LncRNA.annotations["sequence"].empty