fix(config-resolver): check for dot before and after regionRegex match

Author: trivikr

packages/config-resolver/src/regionInfo/getResolvedSigningRegion.spec.ts

@@ -50,7 +50,7 @@ describe(getResolvedSigningRegion.name, () => {
 
   it("returns region from hostname is signingRegion is not present", () => {
     (isFipsRegion as jest.Mock).mockReturnValueOnce(true);
-    const matchSpy = jest.spyOn(String.prototype, "match").mockReturnValueOnce([mockSigningRegion]);
+    const matchSpy = jest.spyOn(String.prototype, "match").mockReturnValueOnce([`.${mockSigningRegion}.`]);
 
     expect(getResolvedSigningRegion(mockRegion, mockOptions)).toEqual(mockSigningRegion);
     expect(matchSpy).toHaveBeenCalledTimes(1);

packages/config-resolver/src/regionInfo/getResolvedSigningRegion.ts

@@ -13,10 +13,10 @@ export const getResolvedSigningRegion = (
   if (signingRegion) {
     return signingRegion;
   } else if (isFipsRegion(region)) {
-    const regionRegexJs = regionRegex.replace("\\\\", "\\").replace(/^\^/g, "").replace(/\$$/g, "");
+    const regionRegexJs = regionRegex.replace("\\\\", "\\").replace(/^\^/g, ".").replace(/\$$/g, ".");
     const regionRegexmatchArray = hostname.match(regionRegexJs);
     if (regionRegexmatchArray) {
-      return regionRegexmatchArray[0];
+      return regionRegexmatchArray[0].slice(1, -1);
     }
   }
 };