diff --git a/test/data/fastq.raw/sc_arobase_1.fq b/test/data/fastq.raw/sc_arobase_1.fq
new file mode 100644
index 0000000000000000000000000000000000000000..f84b165232ddbb3e4dbceecbb0c42122a057835f
--- /dev/null
+++ b/test/data/fastq.raw/sc_arobase_1.fq
@@ -0,0 +1,24 @@
+@SRR2079909.7 7/1
+ATATAGTTACTGTAACTGAATCAATAGTTGCACGTGCTCAAGGAAACTATGCTTCAATAGATAACATAGCTACAGATGTTAAAGCTAAGTTTGGTGATGATACAATTGGTGTTAT
+ATTCCCTATCTTAAGCCGTAACCGTTTTGCTATTTGTTTACGTGGTATTGCTAAAGTCGCTGCTAAGAAAATAGTTTTAATGTTAAGCTACCCATCAGATGAAGTTGGAAATCAC
+TTAGTAGATTTAGATCTTTTAGATGAAAAAGGAGTTAACCCTTGGAC
++
+@C9F9<FF9EF9F9<EF99,CE9,C,,CE,@<C<E8DDF99C8,,CFFCF<EFGF,,C<9,E99C<E9,CEAF989E@FF9,,9EE9,<CEE97C<9FA9FDE9BFFBFFCFGCF
+CGGFGGG9FFGG99<9E7C=FFGGFGGGFGGFFFGFFGGFFCGF7DCEGCFGFCAC4@8>ECEF9,8,=88E8DFEGGC?FAEGAF8EDDEFFCGGCF6D87+=CFG6+D+DDFG
+FFF7C7=ECFFF9CFFFFFF+:6EA@F5C)0)5=@=E?;F9@B:>B6
+@SRR2079909.9 9/1
+TCTAATACTCTAGGAATTCCTCCAATATCACCAAGGTCTAATTTATTGTATTTATATTTTGCACATCCTGCTGTTAAAATTACAGTATCTTTTGGAAGAGCTTTTGCAAAATCTG
+TATAATATTCTCTCGATTTATGTCTTCCATCACACCCTGCCATAACAAAGAACTTCTTTATAGCTCCAGTTTTAACTGCTTCAACAATTTTATCAGCTAATGCTAATACTTGAGC
+ATGTGCAAAACCTCCAACGATTTCTCCATTTTCTATTTCAATTGGCGCTTCACATTTTTTTGCTTGTTCT
++
+@@C--C-<EEF9,,,,CECEEDE8,C8ED,CC98,,CEF,,CEF9FE<E,EFF9F,EEGG,@,C,CCCF,@F8CE9,,,CE9E<,C9FAFFGG9+,6,,,<FFGG,<,,,,CBFC
+F9F9,F9FFDEAAE=8EFGCFAFFGGGFEFG?FAA@CF,=E8FFFFCC8,8:@FGGGGG9FC9DDFCECFDGGGGFG@EFGGCEE?8EFFGDFFA=8FA9D?9FD8B8BFE87+:
+=D==++9996D5DBD?B?>*:A?CEFF7CCCE@E<EEEFC*@@:):8=A>A4>*A<EEEFF>5CE3>EEE
+@SRR2079909.15 15/1
+CTTTCTTACCTGCAAAACTATAAGTTTCATTTTCCTGCTCATCCATCATAGCCATTAAGGAAATCAAGGCAATTAAAAAAGACTTAGAATTCTTTCTTGAAATCATCAAGAAAAC
+AAATCTAAATCTTCGTTTCTTCTTATTATTTTTAAATCTCCATCCATATATATTTCCAAGTATAAAACTTTGAGGTGGTGCTAGATCAATTTTTTCTCCCGCTCTTGCTCCACTT
+GTAAACTTAAAACATGAAGCTACCTTTTCAATTCTTGCCATGATATCTAAATCAA
++
+@CCCCGGFFEG-C89,,CF9E,,6EEFE9FFGGFFG<FFFAFCF8FF9F9,CF9EF99,,,8<FFC9,,C,,EE9<,,97,,CEFE,<,CFFGGGFGG9A8,EFCGGA@,<8@FF
+CD@EFGF9<FFGGGEEFFFGGGGGFGGGGGGGGGFAFFGGGGGGFFGFGFGDGGFGFD99E9DF9E,>DFF,>68@=6C+@EDAFDEF8EFGGGGCGFGE8=>EDF+=@DF?CCF
+7BC7+=CF?C?+@?F5A+<9A8A*:B68AF5EEFEF*>:4C:4A46;E<**9<6=
\ No newline at end of file
diff --git a/test/data/fastq.raw/sc_arobase_2.fq b/test/data/fastq.raw/sc_arobase_2.fq
new file mode 100644
index 0000000000000000000000000000000000000000..4f56b5f307a6f0fd6c036efd21ef68e97ff27174
--- /dev/null
+++ b/test/data/fastq.raw/sc_arobase_2.fq
@@ -0,0 +1,24 @@
+@SRR2079909.7 7/2
+GTCCAAGGGTTAACTCCTTTTTCATCTAAAAGATCTAAATCTACTAAGTGATTTCCAACTTCATCTGATGGGTAGCTTAACATTAAAACTATTTTCTTAGCAGCGCCTTTAGCAA
+TACCACGTAAACAAATAGCAAAACGGTTACGGCTTAAGATAGGGAATATAACACCAATTGTATCATCACCAAACTTAGCTTTAACATCTGTAGCTATGTTATCTATTGAAGCATA
+GTTTCCTTTAGCCCGTGCAACTATTGATTC
++
+@CCCCC9D;FECCFFFFGGGGGGAGGGFCA<FCGGGC<9EFGGGG@9FFAFGGGGGA<FFFE9FGG9,CFC8FCF<FEC9E9FEA,<@BFCFFFGGGGC,C??E+8>CFG99E9,
+EFFC<F7F<B,A:=8B;A:E98,=48CC@F>+=4BB,4,=;B?8,@@9DC,=EDCF8DC=E8=D8DD==?D+8DFD?,8BCF+CD?FGFDD;=DC7C<ED7D9C*;D*0+0;5C+
+3CCCAAAEA**0)11>01=5@@8EE*:6>E
+@SRR2079909.9 9/2
+GTATACAACTGGTGCAGCAGGATTTGATGGATGTGTTCATATCAAAGTAGATGAAAATGGAAAGAAAGATTTTTCAGCCATTATAGAACAAGCAAAAAAATGTGAAGCGCCAATT
+TAAATAGAAAATGGAGAAATCGTTGGAGGTTTTGCACATGCTCAAGTATTAGCATTAGCTGATAAACTTGTTGAAGCAGTTAAAACTGGAGCTATAAAGAAGTTCTTTGTTATTG
+CAGGGTGTGATGGTAGACATAAATCGAGAGACTATTATACATATTTTGCAAAAGCTCTTC
++
+CCCCCF9EFGG8F8FFGG9,C7FGG99FA<8F,C<FGFCF<FF9A<CF9DFFDGAFAFG9FGGGGD@D@FGGGGGDAFF@FGAFC@9EF8DGGGGGDGDGGGGCDFGGGGGCEGG
+,,5AF,?,,AAFF?9F@FFGGEDFEFGEEEGGG8ECEEFFFA=;,9D,EGFFCCDGCFFGGGEE,3,@=DGG+?+6D8=F8D89DFFD56*:DDF7DD+=*DCF@EA@AFFFF*<
+C**):@=@)7=7**3*:;*:**/;64:922))1*8C7@4?<*15@CEF35*8-595BEFF
+@SRR2079909.15 15/2
+CTATTTTGATTTAGATATCATGGCAAGAATTGAAAATGTAGCTTCATGTTTTAAGTTTACAAGTGGAGCAAGAGCGGGAGAAAAAATTGATCTAGCACCACCTCAAAGTTTTATA
+CTTGGAAATATATATGGATGGAGATTTAAAAATAATAAGAAGAAACGAAGATTTAGATTTGTTTTCTTGATGATTTCAAGAAAGAATTCTAAGTCTTTTTTAATTGCCTTGATTT
+CCTTAATGGCTATGATGGATGAGCAGGAAAATGAAACTTATAGTTTTGCAGGTAAGAAAG
++
+CCCCCGGGDGGGGGGGFGGGGGGGCFFFGGGCFDEFGCFF9EEFGFF9FGGGA@<FFGGGDGGGGFFGGGGGFFGE7FEGDCFGG>FFEFGGG9@FFGCADGGGGCGGGGFGGGD
+GGGGGF,?FDGDFFFG9EE:7@:FF;EEEF9@FG9EA999;DF,4DDCE>8EGGFG?FGGGGGGGGGGGGGCCGGGGGG?8?FGGGFGFGFCFFFGFFFFFBCFE7@@EF);CEF
+FFFFCEE;*8@EFAEF<5@EE)77=25):74>>*/:*;CEFF?CCE*(7?:BB=CFEF;;
\ No newline at end of file