Adding check for Nonexistent

include/CLI.hpp

@@ -115,8 +115,11 @@ bool _ExistingDirectory(std::string filename) {
 }
 
 bool _NonexistentPath(std::string filename) {
+    std::cout << "Validating: " << filename << std::endl;
     struct stat buffer;
-    return stat(filename.c_str(), &buffer) != 0;
+    bool out = stat(filename.c_str(), &buffer) != 0;
+    std::cout << (out ? "Passed" : "Failed") << std::endl;
+    return out;
 }
 
 struct Error : public std::runtime_error {
@@ -235,6 +238,12 @@ public:
 
     /// Process the callback
     bool run_callback() const {
+        if(opts.validators.size()>0) {
+            for(const std::string & result : flatten_results())
+                for(const std::function<bool(std::string)> &vali : opts.validators)
+                    if(!vali(result))
+                        return false;
+        }
         return callback(results);
     }
 
@@ -315,6 +324,13 @@ public:
         return out.str();
     }
 
+    std::vector<std::string> flatten_results() const {
+        std::vector<std::string> output;
+        for(const std::vector<std::string> result : results)
+            output.insert(std::end(output), std::begin(result), std::end(result));
+        return output;
+    }
+
 };
 
 

tests/CLITest.cpp

@@ -1,7 +1,7 @@
 
 #include "CLI.hpp"
 #include "gtest/gtest.h"
-
+#include <fstream>
 
 typedef std::vector<std::string> input_t;
 
@@ -205,6 +205,28 @@ TEST_F(TApp, Reset) {
 }
 
 
+TEST_F(TApp, FileNotExists) {
+    std::string myfile{"TestNonFileNotUsed.txt"};
+    EXPECT_TRUE(CLI::_NonexistentPath(myfile));
+
+    std::string filename;
+    app.add_option("file", filename, "", CLI::NonexistentPath);
+    args = {"--file", myfile};
+
+    run();
+    EXPECT_EQ(myfile, filename);
+
+    app.reset();
+
+    
+    bool ok = static_cast<bool>(std::ofstream(myfile.c_str()).put('a')); // create file
+    EXPECT_TRUE(ok);
+    EXPECT_THROW(run(), CLI::ParseError);
+
+    std::remove(myfile.c_str());
+    EXPECT_FALSE(CLI::_ExistingFile(myfile));
+}
+
 TEST_F(TApp, Basic) {
     auto sub1 = app.add_subcommand("sub1");
     auto sub2 = app.add_subcommand("sub2");