Modernize code (clang-tidy -checks='-*,modernize-use-equals-*')

Signed-off-by: Stefan Weil <sw@weilnetz.de>

unittest/imagedata_test.cc

@@ -30,7 +30,7 @@ protected:
     file::MakeTmpdir();
   }
 
-  ImagedataTest() {}
+  ImagedataTest() = default;
 
   // Creates a fake DocumentData, writes it to a file, and returns the filename.
   std::string MakeFakeDoc(int num_pages, unsigned doc_id, std::vector<std::string> *page_texts) {

unittest/lstm_test.h

@@ -50,7 +50,7 @@ protected:
     file::MakeTmpdir();
   }
 
-  LSTMTrainerTest() {}
+  LSTMTrainerTest() = default;
   std::string TestDataNameToPath(const std::string &name) {
     return file::JoinPath(TESTDATA_DIR, "" + name);
   }

unittest/mastertrainer_test.cc

@@ -73,7 +73,7 @@ public:
     false_unichar_id_ = 67;
     false_shape_ = shape_table_->AddShape(false_unichar_id_, 25);
   }
-  ~MockClassifier() override {}
+  ~MockClassifier() override = default;
 
   // Classifies the given [training] sample, writing to results.
   // If debug is non-zero, then various degrees of classifier dependent debug

unittest/resultiterator_test.cc

@@ -31,7 +31,7 @@ protected:
   ResultIteratorTest() {
     src_pix_ = nullptr;
   }
-  ~ResultIteratorTest() override {}
+  ~ResultIteratorTest() override = default;
 
   void SetImage(const char *filename) {
     src_pix_ = pixRead(TestDataNameToPath(filename).c_str());

unittest/tfile_test.cc

@@ -24,7 +24,7 @@ protected:
     std::locale::global(std::locale(""));
   }
 
-  TfileTest() {}
+  TfileTest() = default;
 
   // Some data to serialize.
   class MathData {