Implement target-related methods in Bcf::Header and add corresponding tests

Author: kojix2

lib/hts/bcf/header.rb

@@ -43,6 +43,22 @@ def nsamples
         LibHTS.bcf_hdr_nsamples(@bcf_hdr)
       end
 
+      def target_count
+        target_names.size
+      end
+
+      def get_tid(name)
+        name2id(name)
+      end
+
+      def target_name(rid)
+        id2name(rid)
+      end
+
+      def target_names
+        seqnames
+      end
+
       def samples
         # bcf_hdr_id2name is macro function
         @bcf_hdr[:samples]

test/bcf/header_test.rb

@@ -36,6 +36,26 @@ def test_nsamples
     assert_equal 2, @hdr.nsamples
   end
 
+  def test_target_count
+    assert_equal 4, @hdr.target_count
+  end
+
+  def test_target_name
+    assert_equal "1", @hdr.target_name(0)
+    assert_equal "4", @hdr.target_name(3)
+    assert_nil @hdr.target_name(4)
+  end
+
+  def test_target_names
+    assert_equal %w[1 2 3 4], @hdr.target_names
+  end
+
+  def test_get_tid
+    assert_equal 0, @hdr.get_tid("1")
+    assert_equal 3, @hdr.get_tid("4")
+    assert_equal(-1, @hdr.get_tid("5"))
+  end
+
   def test_samples
     assert_equal %w[A B], @hdr.samples
   end