[libsigcplusplus] tests: Make single argument constructors explicit.

[Murray Cumming <murrayc src gnome org>]

commit 414d9f47f3c7e247c9ecaea9b045a7ee0cb8a371
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Apr 22 10:51:28 2016 +0200

    tests: Make single argument constructors explicit.
    
    Found by the google-explicit-constructor clang-tidy check.

 tests/test_bind.cc        |    2 +-
 tests/test_bind_ref.cc    |    2 +-
 tests/test_bind_refptr.cc |    2 +-
 tests/test_bind_return.cc |    2 +-
 tests/test_track_obj.cc   |    2 +-
 tests/test_visit_each.cc  |    4 ++--
 6 files changed, 7 insertions(+), 7 deletions(-)
---
diff --git a/tests/test_bind.cc b/tests/test_bind.cc
index 44e0c2e..949d052 100644
--- a/tests/test_bind.cc
+++ b/tests/test_bind.cc
@@ -68,7 +68,7 @@ egon(std::string& str)
 
 struct book : public sigc::trackable
 {
-  book(const std::string& name) : name_(name) {}
+  explicit book(const std::string& name) : name_(name) {}
 
   // non-copyable:
   book(const book&) = delete;
diff --git a/tests/test_bind_ref.cc b/tests/test_bind_ref.cc
index a83fbae..fd1fb4e 100644
--- a/tests/test_bind_ref.cc
+++ b/tests/test_bind_ref.cc
@@ -16,7 +16,7 @@ std::ostringstream result_stream;
 class Param : public sigc::trackable
 {
 public:
-  Param(const std::string& name) : name_(name) {}
+  explicit Param(const std::string& name) : name_(name) {}
 
   // non-copyable,
   // so it can only be used with sigc::bind() via sigc::ref()
diff --git a/tests/test_bind_refptr.cc b/tests/test_bind_refptr.cc
index 062cb7d..8bc59b8 100644
--- a/tests/test_bind_refptr.cc
+++ b/tests/test_bind_refptr.cc
@@ -86,7 +86,7 @@ public:
    * Increments the reference count.
    */
   template <typename T_CastFrom>
-  inline RefPtr(const RefPtr<T_CastFrom>& src);
+  inline explicit RefPtr(const RefPtr<T_CastFrom>& src);
 
   /** Swap the contents of two RefPtr<>.
    * This method swaps the internal pointers to T_CppObject.  This can be
diff --git a/tests/test_bind_return.cc b/tests/test_bind_return.cc
index 7aa38a7..bb224bc 100644
--- a/tests/test_bind_return.cc
+++ b/tests/test_bind_return.cc
@@ -27,7 +27,7 @@ struct foo
 
 struct bar : public sigc::trackable
 {
-  bar(int i = 0) : i_(i) {}
+  explicit bar(int i = 0) : i_(i) {}
   operator int() { return i_; }
   int i_;
 };
diff --git a/tests/test_track_obj.cc b/tests/test_track_obj.cc
index 46f432e..2d29f4b 100644
--- a/tests/test_track_obj.cc
+++ b/tests/test_track_obj.cc
@@ -62,7 +62,7 @@ class Functor1
 public:
   using result_type = std::string;
 
-  Functor1(const bar_group4& bar) : bar_(bar) {}
+  explicit Functor1(const bar_group4& bar) : bar_(bar) {}
 
   std::string operator()(int i) { return (i < 0) ? "negative" : ((i > 0) ? "positive" : "zero"); }
 
diff --git a/tests/test_visit_each.cc b/tests/test_visit_each.cc
index ade8337..0d081d1 100644
--- a/tests/test_visit_each.cc
+++ b/tests/test_visit_each.cc
@@ -59,7 +59,7 @@ namespace
 class MyClass1 : public sigc::trackable
 {
 public:
-  MyClass1(const std::string& str) : s(str) {}
+  explicit MyClass1(const std::string& str) : s(str) {}
 
   void execute(int i) { result_stream << s << i; }
 private:
@@ -69,7 +69,7 @@ private:
 class MyClass2 : public ns_ext::NsExtClass, public sigc::trackable
 {
 public:
-  MyClass2(const std::string& str) : s(str) {}
+  explicit MyClass2(const std::string& str) : s(str) {}
 
   void execute(int i) { result_stream << s << i; }
 private: