Add basic test for marshalling bank statement request

Also add marshalCheckRequest(), a helper function which prints the first
differences found between the two strings to aid in debugging test
failures.

request_test.go

@@ -0,0 +1,48 @@
+package ofxgo_test
+
+import (
+	"github.com/aclindsa/ofxgo"
+	"regexp"
+	"testing"
+)
+
+var ignoreSpacesRe = regexp.MustCompile(">[ \t\r\n]+<")
+
+func marshalCheckRequest(t *testing.T, request *ofxgo.Request, expected string) {
+	buf, err := request.Marshal()
+	if err != nil {
+		t.Fatalf("Unexpected error marshalling request: %s\n", err)
+	}
+	actualString := buf.String()
+
+	// Ignore spaces between XML elements
+	expectedString := ignoreSpacesRe.ReplaceAllString(expected, "><")
+	actualString = ignoreSpacesRe.ReplaceAllString(actualString, "><")
+
+	if expectedString != actualString {
+		compareLength := len(expectedString)
+		if len(actualString) < compareLength {
+			compareLength = len(actualString)
+		}
+
+		for i := 0; i < compareLength; i++ {
+			if expectedString[i] != actualString[i] {
+				displayStart := i - 10
+				if displayStart < 0 {
+					displayStart = 0
+				}
+				displayEnd := displayStart + 40
+				if displayEnd > compareLength {
+					displayEnd = compareLength
+				}
+				t.Fatalf("%s expected '...%s...',\ngot '...%s...'\n", t.Name(), expectedString[displayStart:displayEnd], actualString[displayStart:displayEnd])
+			}
+		}
+
+		if len(actualString) > compareLength {
+			t.Fatalf("%s: Actual string longer than expected string\n", t.Name())
+		} else {
+			t.Fatalf("%s: Actual string shorter than expected string\n", t.Name())
+		}
+	}
+}