Add test files as dune dep

- Also add `fma` test file
- Fix OCaml lower bound

decimal.opam

@@ -1,6 +1,6 @@
 # This file is generated by dune, edit dune-project instead
 opam-version: "2.0"
-version: "v0.1.0"
+version: "v0.1.1"
 synopsis: "Arbitrary-precision floating-point decimal library"
 description: """
 Arbitrary-precision floating-point decimal library ported from
@@ -14,7 +14,7 @@ bug-reports: "https://github.com/yawaramin/ocaml-decimal/issues"
 depends: [
   "dune" {>= "2.7"}
   "angstrom" {>= "0.15.0" & < "1.0.0" & with-test}
-  "ocaml" {>= "4.06.0"}
+  "ocaml" {>= "4.08.0"}
   "zarith" {>= "1.10" & < "2.0.0"}
   "odoc" {with-doc}
 ]

dune-project

@@ -1,7 +1,7 @@
 (lang dune 2.7)
 
 (name decimal)
-(version v0.1.0)
+(version v0.1.1)
 (generate_opam_files true)
 (license PSF-2.0)
 (authors "Yawar Amin <[email protected]>")
@@ -16,5 +16,5 @@ the Python decimal module.")
   (documentation "https://yawaramin.github.io/ocaml-decimal/api")
   (depends
     (angstrom (and (>= 0.15.0) (< 1.0.0) :with-test))
-    (ocaml (>= 4.06.0))
+    (ocaml (>= 4.08.0))
     (zarith (and (>= 1.10) (< 2.0.0)))))

lib/decimal.ml

@@ -492,6 +492,7 @@ let zero_pad_right n string =
 let zero_pad_left n string =
   if n < 1 then string
   else String.make n '0' ^ string
+
 module Round = struct
   (* For each rounding function below: