Add test case

Author: tomhollingworth

Diff for: cmd/merge/merge_test.go

@@ -0,0 +1,42 @@
+package main_test
+
+import (
+	"os"
+	"testing"
+
+	merge "github.com/libremfg/go-tools/cmd/merge"
+)
+
+func TestMerge(t *testing.T) {
+	d := "./test/"
+	e := []string{".txt"}
+	o := "./output"
+	v := false
+
+	t.Cleanup(func() {
+		_, err := os.Stat(o)
+		if err == nil {
+			os.Remove(o)
+		}
+	})
+
+	merge.Merge(d, e, o, v)
+
+	expect := []byte("1\r\n2\r\n3\r\n")
+
+	actual, err := os.ReadFile(o)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if len(expect) != len(actual) {
+		t.Errorf("lengths don't match expect %d got %d", len(expect), len(actual))
+		return
+	}
+
+	for i := 0; i < len(expect); i++ {
+		if expect[i] != actual[i] {
+			t.Errorf("index %d don't match expect %b got %b", i, expect[i], actual[i])
+		}
+	}
+}

Diff for: cmd/merge/test/file1.txt

@@ -0,0 +1 @@
+1

Diff for: cmd/merge/test/file2.txt

@@ -0,0 +1 @@
+2

Diff for: cmd/merge/test/file3.txt

@@ -0,0 +1 @@
+3