fmt: fix panic on width argument

tests/by-util/test_fmt.rs

@@ -43,3 +43,34 @@ fn test_fmt_width_too_big() {
             .stderr_is("fmt: invalid width: '2501': Numerical result out of range\n");
     }
 }
+
+#[test]
+fn test_fmt_goal() {
+    for param in ["-g", "--goal"] {
+        new_ucmd!()
+            .args(&["one-word-per-line.txt", param, "7"])
+            .succeeds()
+            .stdout_is("this is\na file\nwith one\nword per\nline\n");
+    }
+}
+
+#[test]
+fn test_fmt_goal_too_big() {
+    for param in ["-g", "--goal"] {
+        new_ucmd!()
+            .args(&["one-word-per-line.txt", "--width=75", param, "76"])
+            .fails()
+            .code_is(1)
+            .stderr_is("fmt: GOAL cannot be greater than WIDTH.\n");
+    }
+}
+
+#[test]
+fn test_fmt_set_goal_not_contain_width() {
+    for param in ["-g", "--goal"] {
+        new_ucmd!()
+            .args(&["one-word-per-line.txt", param, "74"])
+            .succeeds()
+            .stdout_is("this is a file with one word per line\n");
+    }
+}