cleaned code, improved docs and tests

Signed-off-by: Matt Butcher <matt.butcher@microsoft.com>

Makefile

@@ -15,11 +15,12 @@ build:
 .PHONY: test-unit
 test-unit:
 	grain tests.gr
-	
+
 .PHONY: test
 test:build
 test: test-unit
 test:
+	@echo EXPECT: Loading file fileserver.gr
 	wasmtime --dir . --env PATH_INFO=${PATH_INFO} \
 	--env X_MATCHED_ROUTE=${X_MATCHED_ROUTE} \
 	fileserver.gr.wasm > /dev/null

README.md

@@ -27,10 +27,26 @@ To compile:
 $ make build
 ```
 
-To run test (Wasmtime required):
+You can run unit tests with `make test-unit` or full tests with `make test`:
 
 ```
 $ make test
+grain compile fileserver.gr
+grain tests.gr
+✅ PASS         Env.splitEnvVar should parse
+✅ PASS         Util.reverse should reverse string
+✅ PASS         Util.lastIndexOf should find Some
+===== Expected: =====
+Some(19)
+======= Got: ========
+Some(18)
+=====================
+⛔️ FAIL         UtillastIndexOf should find Some
+✅ PASS         Util.lastIndexOf should find None
+✅ PASS         Mediatype.guess should find text/plain
+✅ PASS         Mediatype.guess should find default type
+❌ Total failed tests: 1❌
+make: *** [test-unit] Error 1
 ```
 
 ## Running in Wagi

fileserver.gr

@@ -6,6 +6,7 @@ import Option from "option"
 import File from "sys/file"
 import String from "string"
 import Mediatype from "./lib/mediatype"
+import Stringutil from "./lib/stringutil"
 
 let serve = (path) => {
     File.fdWrite(File.stderr, "Fileserver: Loading file ")
@@ -45,11 +46,8 @@ let serve = (path) => {
 
 let guestpath = (env) => {
     let req = Option.unwrap(Map.get("PATH_INFO", env))
-    let mut base = Option.unwrap(Map.get("X_MATCHED_ROUTE", env))
-    let dots = String.indexOf("/...", base)
-    if (Option.isSome(dots) ) {
-        base = String.slice(0, Option.unwrap(dots), base)
-    }
+    let matched = Option.unwrap(Map.get("X_MATCHED_ROUTE", env))
+    let base = Stringutil.beforeLast("/...", matched)
     String.slice(String.length(base) + 1, String.length(req), req)
 }
 

lib/stringutil.gr

@@ -16,15 +16,35 @@ export let reverse = (str: String) => {
 }
 
 // Get the index of the last appearance of needle in the haystack.
+//
+// For a multi-character needle, this will return the end of that sequence,
+// not the beginning (as indexOf does).
+//
 // @param needle: The string to search for
 // @param haystack: The string to be searched
 // @return Option<Number> The offset, if found, or a number
 export let lastIndexOf = (needle: String, haystack: String) => {
     let rev = reverse(haystack)
     let revNeedle = reverse(needle)
+    let nlen = String.length(needle)
     let i = String.indexOf(revNeedle, rev)
     match (i) {
         Some(offset) => Some(String.length(haystack) - 1 - offset),
         None => None,   
     }
 }
+
+export let afterLast = (needle: String, haystack: String) => {
+    match (lastIndexOf(needle, haystack)) {
+        Some(index) => String.slice(index + 1, String.length(haystack), haystack),
+        None => haystack
+    }
+}
+
+export let beforeLast = (needle: String, haystack: String) => {
+    let nlen = String.length(needle)
+    match (lastIndexOf(needle, haystack)) {
+        Some(index) => String.slice(0, index + 1 - nlen, haystack),
+        None => haystack
+    }
+}

tests.gr

@@ -12,6 +12,11 @@ let check = (a, b, msg: String) => {
         true => Ok(String.concat("✅ PASS\t\t", msg)),
         _  => {
             totalErr += 1
+            print("===== Expected: =====")
+            print(a)
+            print("======= Got: ========")
+            print(b)
+            print("=====================")
             Err(String.concat("⛔️ FAIL\t\t", msg))
         }
     }
@@ -35,8 +40,13 @@ let report = () => {
 
 expect(("a", "b"), Env.splitEnvVar("a=b"), "Env.splitEnvVar should parse")
 expect("gfedcba", Util.reverse("abcdefg"), "Util.reverse should reverse string")
-expect(Some(5), Util.lastIndexOf("/.", "aaaa/."), "UtillastIndexOf should find Some")
+expect(Some(5), Util.lastIndexOf("/.", "aaaa/."), "Util.lastIndexOf should find Some")
+expect(Some(18), Util.lastIndexOf(".", "aaaa/fileserver.gr.wasm"), "Util.lastIndexOf should find last dot, not first dot")
+expect(Some(12), Util.lastIndexOf(".", "/.../aaaa/..."), "Util.lastIndexOf should find last set of three dots")
 expect(None, Util.lastIndexOf("??", "aaaa.."), "Util.lastIndexOf should find None")
+expect("test", Util.afterLast("$.$", "foo$.$bar$.$test"), "Util.afterLast should find last match")
+expect("/prefix/../path", Util.beforeLast("/..", "/prefix/../path/.."), "Util.beforeLast should return first part")
+expect("/prefix/../path/..", Util.beforeLast("/$$", "/prefix/../path/.."), "Util.beforeLast should return entire string when no match")
 expect("text/plain", Mediatype.guess("foo.txt"), "Mediatype.guess should find text/plain")
 expect("application/octet-stream", Mediatype.guess("foo.MADEUP"), "Mediatype.guess should find default type")