Accept only-one-sample per project as input to QuaC

QuaC fails when only one sample in input ped file (#34 (closed)). This MR fixes this issue by removing filepath globbing. This MR further adds a system-level testing to capture such errors in future (#35 (closed)).

workflow/rules/coverage_analysis.smk

@@ -154,12 +154,11 @@ rule indexcov:
         str(WORKFLOW_PATH / "configs/env/goleft.yaml")
     params:
         outdir=lambda wildcards, output: Path(output[0]).parent,
-        infiles=lambda wildcards: str(PROJECT_PATH / f"{{{','.join(SAMPLES)}}}" / "bam" / "*.bam"),
     shell:
         r"""
         goleft indexcov \
             --directory {params.outdir} \
-            {params.infiles} \
+            {input.bam} \
             > {log} 2>&1
         """