diff --git a/internal/cmd/utils_test.go b/internal/cmd/utils_test.go
new file mode 100644
index 0000000..3e46c39
--- /dev/null
+++ b/internal/cmd/utils_test.go
@@ -0,0 +1,145 @@
+package cmd
+
+import (
+	"reflect"
+	"testing"
+)
+
+func Test_normalizeSpace(t *testing.T) {
+	tests := []struct {
+		name string
+		args string
+		want string
+	}{{
+		name: "normal sentence",
+		args: "What a perfect, beautiful sentence",
+		want: "What a perfect, beautiful sentence",
+	}, {
+		name: "has unnecessary space before and after sentence",
+		args: "    I'm surrounded with spaces    ",
+		want: "I'm surrounded with spaces",
+	}, {
+		name: "has unnecessary spaces in middle of sentence",
+		args: "I'm hollow         inside",
+		want: "I'm hollow inside",
+	}, {
+		name: "has unnecessary new line in middle of sentence",
+		args: "I'm broken \n\n\ninside",
+		want: "I'm broken inside",
+	}, {
+		name: "has unnecessary new line and spaces everywhere",
+		args: "    I'm hollow     broken\n\n\n\nand surrounded by spaces    ",
+		want: "I'm hollow broken and surrounded by spaces",
+	}}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := normalizeSpace(tt.args); got != tt.want {
+				t.Errorf("normalizeSpace() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_isURLValid(t *testing.T) {
+	tests := []struct {
+		name string
+		args string
+		want bool
+	}{{
+		name: "valid URL",
+		args: "https://www.google.com",
+		want: true,
+	}, {
+		name: "valid localhost URL",
+		args: "http://localhost:8080",
+		want: true,
+	}, {
+		name: "valid non-HTTP URL",
+		args: "ftp://www.example.com/storage",
+		want: true,
+	}, {
+		name: "invalid URL",
+		args: "https:/www.google.com",
+		want: false,
+	}, {
+		name: "hash URL",
+		args: "#some-awesome-heading",
+		want: false,
+	}, {
+		name: "relative URL",
+		args: "/page/contact",
+		want: false,
+	}}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := isURLValid(tt.args); got != tt.want {
+				t.Errorf("isURLValid() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_parseStrIndices(t *testing.T) {
+	tests := []struct {
+		name    string
+		args    []string
+		want    []int
+		wantErr bool
+	}{{
+		name:    "single number",
+		args:    []string{"1"},
+		want:    []int{1},
+		wantErr: false,
+	}, {
+		name:    "multiple number",
+		args:    []string{"1", "2", "3"},
+		want:    []int{1, 2, 3},
+		wantErr: false,
+	}, {
+		name:    "single ranged number",
+		args:    []string{"1-5"},
+		want:    []int{1, 2, 3, 4, 5},
+		wantErr: false,
+	}, {
+		name:    "multiple ranged number",
+		args:    []string{"1-5", "8-9"},
+		want:    []int{1, 2, 3, 4, 5, 8, 9},
+		wantErr: false,
+	}, {
+		name:    "mixed single and ranged number",
+		args:    []string{"1-5", "8-9", "11", "12"},
+		want:    []int{1, 2, 3, 4, 5, 8, 9, 11, 12},
+		wantErr: false,
+	}, {
+		name:    "invalid number",
+		args:    []string{"AAA"},
+		want:    nil,
+		wantErr: true,
+	}, {
+		name:    "mixed number and string",
+		args:    []string{"1", "2", "A"},
+		want:    nil,
+		wantErr: true,
+	}, {
+		name:    "reversed ranged number",
+		args:    []string{"5-1"},
+		want:    nil,
+		wantErr: true,
+	}}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := parseStrIndices(tt.args)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("parseStrIndices() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("parseStrIndices() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}