Adds some unit test

Former-commit-id: b1a59df1c87187a1538f30c447d42bbe96402419

pkg/obiseq/subseq.go

@@ -5,8 +5,16 @@ import (
 	"fmt"
 )
 
-// Returns a sub sequence start from position 'from' included,
-// to position 'to' excluded. Coordinates start at position 0.
+// Subsequence returns a subsequence of the BioSequence.
+//
+// Parameters:
+// - from: starting position of the subsequence.
+// - to: ending position of the subsequence.
+// - circular: indicates whether the subsequence should be circular.
+//
+// Return:
+// - *BioSequence: the subsequence of the BioSequence.
+// - error: an error if the subsequence parameters are invalid.
 func (sequence *BioSequence) Subsequence(from, to int, circular bool) (*BioSequence, error) {
 	if from >= to && !circular {
 		return nil, errors.New("from greater than to")

pkg/obiseq/subseq_test.go

@@ -0,0 +1,48 @@
+package obiseq
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSubsequence(t *testing.T) {
+	// Test case 1: Subsequence with valid parameters and non-circular
+	seq := NewBioSequence("ID1", []byte("ATCG"), "")
+	sub, err := seq.Subsequence(1, 3, false)
+	assert.NoError(t, err)
+	assert.Equal(t, []byte("tc"), sub.Sequence())
+
+	seq = NewBioSequenceWithQualities("ID1", []byte("ATCG"), "", []byte{40, 30, 20, 10})
+	sub, err = seq.Subsequence(1, 3, false)
+	assert.NoError(t, err)
+	assert.Equal(t, []byte("tc"), sub.Sequence())
+	assert.Equal(t, Quality([]byte{30, 20}), sub.Qualities())
+
+	// Test case 2: Subsequence with valid parameters and circular
+	seq2 := NewBioSequence("ID1", []byte("ATCG"), "")
+	sub2, err2 := seq2.Subsequence(3, 2, true)
+	assert.NoError(t, err2)
+	assert.Equal(t, []byte("gat"), sub2.Sequence())
+
+	seq = NewBioSequenceWithQualities("ID1", []byte("ATCG"), "", []byte{40, 30, 20, 10})
+	sub, err = seq.Subsequence(3, 2, true)
+	assert.NoError(t, err)
+	assert.Equal(t, []byte("gat"), sub.Sequence())
+	assert.Equal(t, Quality([]byte{10, 40, 30}), sub.Qualities())
+
+	// Test case 3: Subsequence with from greater than to and non-circular
+	seq3 := NewBioSequence("ID1", []byte("ATCG"), "")
+	_, err3 := seq3.Subsequence(3, 1, false)
+	assert.EqualError(t, err3, "from greater than to")
+
+	// Test case 4: Subsequence with from out of bounds
+	seq4 := NewBioSequence("ID1", []byte("ATCG"), "")
+	_, err4 := seq4.Subsequence(-1, 2, false)
+	assert.EqualError(t, err4, "from out of bounds")
+
+	// Test case 5: Subsequence with to out of bounds
+	seq5 := NewBioSequence("ID1", []byte("ATCG"), "")
+	_, err5 := seq5.Subsequence(2, 5, false)
+	assert.EqualError(t, err5, "to out of bounds")
+}