diff --git a/README.md b/README.md
index 11ee5a9..c2d2af6 100644
--- a/README.md
+++ b/README.md
@@ -410,9 +410,15 @@ work by you shall be dual licensed as above, without any additional terms or con
 
 ## Version History
 
+#### Development
+
+* Fix bug where requests constructed from a `URL` would not inherit environmental defaults (e.g. auth, headers, etc) ([#52][]).
+
+[#52]: https://github.com/postmates/PMHTTP/issues/52 "Requests constructed with relative URLs do not inherit environment configuration · Issue #52 · postmates/PMHTTP"
+
 #### v4.3.1 (2018-08-01)
 
-* Add `URLProtocol` method overloads to query and set protocol properties on `HTTPManagerRequest`s ([#43][])
+* Add `URLProtocol` method overloads to query and set protocol properties on `HTTPManagerRequest`s ([#43][]).
 
 [#43]: https://github.com/postmates/PMHTTP/issues/43 "Let me attach arbitrary URLProtocol properties to a request · Issue #43 · postmates/PMHTTP"
 
diff --git a/Sources/HTTPManager.swift b/Sources/HTTPManager.swift
index a7aad76..587192a 100644
--- a/Sources/HTTPManager.swift
+++ b/Sources/HTTPManager.swift
@@ -1173,15 +1173,14 @@ extension HTTPManager {
     private func constructRequest<T: HTTPManagerRequest>(_ url: URL, f: (URL) -> T) -> T {
         let info = _configureRequestInfo()
         let request: T
+        var url = url
         if url.scheme == nil {
             // try to make it relative to the environment. This shouldn't fail, but in case it does
             // for some reason, just fall back to using the relative URL, which should produce a URL
             // loading error later. This allows us to preserve the non-optional return type.
-            let url_ = NSURL(string: url.absoluteString, relativeTo: environment?.baseURL) as URL? ?? url
-            request = f(url_)
-        } else {
-            request = f(url)
+            url = NSURL(string: url.absoluteString, relativeTo: environment?.baseURL) as URL? ?? url
         }
+        request = f(url)
         _configureRequest(request, url: url, with: info)
         return request
     }
diff --git a/Tests/AuthTests.swift b/Tests/AuthTests.swift
index bd21ebc..e95b1ce 100644
--- a/Tests/AuthTests.swift
+++ b/Tests/AuthTests.swift
@@ -86,23 +86,32 @@ final class AuthTests: PMHTTPTestCase {
     
     func testAuthEnvironmentDefaults() {
         HTTP.environment = HTTPManagerEnvironment(string: "http://\(httpServer.address)/v1")!
-        
         HTTP.defaultAuth = HTTPBasicAuth(username: "alice", password: "secure")
-        var req = HTTP.request(GET: "foo")!
-        XCTAssertNotNil(req.auth, "request auth")
-        req = HTTP.request(GET: "")!
-        XCTAssertNotNil(req.auth, "request auth")
-        req = HTTP.request(GET: "/foo")!
-        XCTAssertNil(req.auth, "request auth")
-        req = HTTP.request(GET: "/v1/foo")!
-        XCTAssertNotNil(req.auth, "request auth")
-        req = HTTP.request(GET: "http://\(httpServer.address)/v1/")!
-        XCTAssertNotNil(req.auth, "request auth")
-        req = HTTP.request(GET: "http://apple.com/v1")!
-        XCTAssertNil(req.auth, "request auth")
         
-        req.setDefaultEnvironmentalProperties()
-        XCTAssertNotNil(req.auth, "request auth")
+        func assertAuthNotNil(for path: String, preprocess: ((HTTPManagerDataRequest) -> Void)? = nil, line: UInt = #line) {
+            var req = HTTP.request(GET: path)!
+            preprocess?(req)
+            XCTAssertNotNil(req.auth, "request.auth - string", line: line)
+            req = HTTP.request(GET: NSURL(string: path)! as URL)
+            preprocess?(req)
+            XCTAssertNotNil(req.auth, "request.auth - URL", line: line)
+        }
+        func assertAuthNil(for path: String, preprocess: ((HTTPManagerDataRequest) -> Void)? = nil, line: UInt = #line) {
+            var req = HTTP.request(GET: path)!
+            preprocess?(req)
+            XCTAssertNil(req.auth, "request.auth - string", line: line)
+            req = HTTP.request(GET: NSURL(string: path)! as URL)
+            preprocess?(req)
+            XCTAssertNil(req.auth, "request.auth - URL", line: line)
+        }
+        
+        assertAuthNotNil(for: "foo")
+        assertAuthNotNil(for: "")
+        assertAuthNil(for: "/foo")
+        assertAuthNotNil(for: "/v1/foo")
+        assertAuthNotNil(for: "http://\(httpServer.address)/v1/")
+        assertAuthNil(for: "http://apple.com/v1")
+        assertAuthNotNil(for: "http://apple.com/v1", preprocess: { $0.setDefaultEnvironmentalProperties() })
     }
     
     func testRetryAuthInteraction() {
diff --git a/Tests/PMHTTPTests.swift b/Tests/PMHTTPTests.swift
index 970daf8..862fa99 100644
--- a/Tests/PMHTTPTests.swift
+++ b/Tests/PMHTTPTests.swift
@@ -1791,43 +1791,54 @@ final class PMHTTPTests: PMHTTPTestCase {
     func testServerRequiresContentLengthEnvironmentDefaults() {
         HTTP.environment = HTTPManagerEnvironment(string: "http://\(httpServer.address)/v1")!
         
-        HTTP.defaultServerRequiresContentLength = true
-        var req = HTTP.request(GET: "foo")!
-        XCTAssertTrue(req.serverRequiresContentLength, "request serverRequiresContentLength")
-        req = HTTP.request(GET: "")!
-        XCTAssertTrue(req.serverRequiresContentLength, "request serverRequiresContentLength")
-        req = HTTP.request(GET: "/foo")!
-        XCTAssertFalse(req.serverRequiresContentLength, "request serverRequiresContentLength")
-        req = HTTP.request(GET: "/v1/foo")!
-        XCTAssertTrue(req.serverRequiresContentLength, "request serverRequiresContentLength")
-        req = HTTP.request(GET: "http://\(httpServer.address)/v1/")!
-        XCTAssertTrue(req.serverRequiresContentLength, "request serverRequiresContentLength")
-        req = HTTP.request(GET: "http://apple.com/v1")!
-        XCTAssertFalse(req.serverRequiresContentLength, "request serverRequiresContentLength")
+        func assertServerRequiresContentLength(for path: String, preprocess: ((HTTPManagerDataRequest) -> Void)? = nil, equals expected: Bool, line: UInt = #line) {
+            HTTP.defaultServerRequiresContentLength = true
+            let assert = (expected ? XCTAssertTrue : XCTAssertFalse)
+            var req = HTTP.request(GET: path)!
+            preprocess?(req)
+            assert(req.serverRequiresContentLength, "request.serverRequiresContentLength - string", #file, line)
+            req = HTTP.request(GET: NSURL(string: path)! as URL)
+            preprocess?(req)
+            assert(req.serverRequiresContentLength, "request.serverRequiresContentLength - URL", #file, line)
+            
+            HTTP.defaultServerRequiresContentLength = false
+            req = HTTP.request(GET: path)
+            preprocess?(req)
+            XCTAssertFalse(req.serverRequiresContentLength, "request.serverRequiresContentLength default false - string", line: line)
+            req = HTTP.request(GET: NSURL(string: path)! as URL)
+            preprocess?(req)
+            XCTAssertFalse(req.serverRequiresContentLength, "request.serverRequiresContentLength default false - URL", line: line)
+        }
         
-        req.setDefaultEnvironmentalProperties()
-        XCTAssertTrue(req.serverRequiresContentLength, "request serverRequiresContentLength")
+        assertServerRequiresContentLength(for: "foo", equals: true)
+        assertServerRequiresContentLength(for: "", equals: true)
+        assertServerRequiresContentLength(for: "/foo", equals: false)
+        assertServerRequiresContentLength(for: "/v1/foo", equals: true)
+        assertServerRequiresContentLength(for: "http://\(httpServer.address)/v1/", equals: true)
+        assertServerRequiresContentLength(for: "http://apple.com/v1", equals: false)
+        assertServerRequiresContentLength(for: "http://apple.com/v1", preprocess: { $0.setDefaultEnvironmentalProperties() }, equals: true)
     }
     
     func testHeaderFieldsEnvironmentDefaults() {
         HTTP.environment = HTTPManagerEnvironment(string: "http://\(httpServer.address)/v1")!
         HTTP.defaultHeaderFields = ["X-Foo": "Bar"]
         
-        var req = HTTP.request(GET: "foo")!
-        XCTAssertEqual(req.headerFields, ["X-Foo": "Bar"], "request headerFields")
-        req = HTTP.request(GET: "")!
-        XCTAssertEqual(req.headerFields, ["X-Foo": "Bar"], "request headerFields")
-        req = HTTP.request(GET: "/foo")!
-        XCTAssertEqual(req.headerFields, [:], "request headerFields")
-        req = HTTP.request(GET: "/v1/foo")!
-        XCTAssertEqual(req.headerFields, ["X-Foo": "Bar"], "request headerFields")
-        req = HTTP.request(GET: "http://\(httpServer.address)/v1/")!
-        XCTAssertEqual(req.headerFields, ["X-Foo": "Bar"], "request headerFields")
-        req = HTTP.request(GET: "http://apple.com/v1")!
-        XCTAssertEqual(req.headerFields, [:], "request headerFields")
+        func assertHeaders(for path: String, preprocess: ((HTTPManagerDataRequest) -> Void)? = nil, equals expected: HTTPManagerRequest.HTTPHeaders, line: UInt = #line) {
+            var req = HTTP.request(GET: path)!
+            preprocess?(req)
+            XCTAssertEqual(req.headerFields, expected, "request.headerFields - string", line: line)
+            req = HTTP.request(GET: NSURL(string: path)! as URL)
+            preprocess?(req)
+            XCTAssertEqual(req.headerFields, expected, "request.headerFields - URL", line: line)
+        }
         
-        req.setDefaultEnvironmentalProperties()
-        XCTAssertEqual(req.headerFields, ["X-Foo": "Bar"], "request headerFields")
+        assertHeaders(for: "foo", equals: ["X-Foo": "Bar"])
+        assertHeaders(for: "", equals: ["X-Foo": "Bar"])
+        assertHeaders(for: "/foo", equals: [:])
+        assertHeaders(for: "/v1/foo", equals: ["X-Foo": "Bar"])
+        assertHeaders(for: "http://\(httpServer.address)/v1/", equals: ["X-Foo": "Bar"])
+        assertHeaders(for: "http://apple.com/v1", equals: [:])
+        assertHeaders(for: "http://apple.com/v1", preprocess: { $0.setDefaultEnvironmentalProperties() }, equals: ["X-Foo": "Bar"])
     }
     
     func testSetDefaultEnvironmentalPropertiesHeaderFieldsMerge() {