added test for Tbx

Author: Jim Havrilla

hts/test/test_tbx.py

@@ -0,0 +1,18 @@
+import os
+from hts import Tbx
+from nose.tools import assert_raises
+
+HERE = os.path.dirname(__file__)
+GTF = os.path.join(HERE, "example.gtf.gz")
+BAM = os.path.join(HERE, "e.sam")
+
+def test_build():
+    if os.path.exists(GTF + ".tbi"):
+        os.unlink(GTF + ".tbi")
+    t = Tbx(GTF)
+    assert t._tbx 
+    assert os.path.exists(GTF + ".tbi")
+
+def test_error_on_bad_file():
+    assert_raises(Exception, Tbx, BAM)
+