Honor SSL config settings for ValidatorSites:

FIXES: #2990

* refactor common SSL client setup
* enable SSL in unit-test http server
* add tests for SSLHTTPDownloader
* misc test refactoring

src/test/unit_test/FileDirGuard.h

@@ -111,18 +111,23 @@ class FileDirGuard : public DirGuard
 {
 protected:
     path const file_;
+    bool created_ = false;
 
 public:
     FileDirGuard(beast::unit_test::suite& test,
         path subDir, path file, std::string const& contents,
-        bool useCounter = true)
+        bool useCounter = true, bool create = true)
         : DirGuard(test, subDir, useCounter)
         , file_(file.is_absolute()  ? file : subdir() / file)
     {
         if (!exists (file_))
         {
-            std::ofstream o (file_.string ());
-            o << contents;
+            if (create)
+            {
+                std::ofstream o (file_.string ());
+                o << contents;
+                created_ = true;
+            }
         }
         else
         {
@@ -137,11 +142,16 @@ public:
         try
         {
             using namespace boost::filesystem;
-            if (!exists (file_))
-                test_.log << "Expected " << file_.string ()
-                << " to be an existing file." << std::endl;
-            else
+            if (exists (file_))
+            {
                 remove (file_);
+            }
+            else
+            {
+                if (created_)
+                    test_.log << "Expected " << file_.string ()
+                    << " to be an existing file." << std::endl;
+            }
         }
         catch (std::exception& e)
         {

src/test/unit_test/SuiteJournal.h

@@ -94,6 +94,29 @@ public:
     operator beast::Journal&() { return journal_; }
 };
 
+// this sink can be used to create a custom journal
+// whose log messages will be captured to a stringstream
+// that can be later inspected.
+class StreamSink : public beast::Journal::Sink
+{
+    std::stringstream strm_;
+public:
+    StreamSink (
+        beast::severities::Severity threshold = beast::severities::kDebug)
+    : Sink (threshold, false) {  }
+
+    void
+    write (beast::severities::Severity level,
+        std::string const& text) override
+    {
+        if (level < threshold())
+            return;
+
+        strm_ << text << std::endl;
+    }
+    std::stringstream const& messages() const { return strm_ ; }
+};
+
 } // test
 } // ripple