VelocityWave() method added to StopwatchSagger.

- Just exposed read-only access to a private class member. The
  information would be good to know.

Author: bretzel12

include/models/sagging/stopwatch_sagger.h

@@ -37,6 +37,10 @@ class StopwatchSagger {
   bool Validate(const bool& is_included_warnings = true,
                 std::list<ErrorMessage>* messages = nullptr) const;
 
+  /// \brief Gets the traveling wave velocity.
+  /// \return The traveling wave velocity.
+  double VelocityWave() const;
+
   /// \brief Gets the catenary.
   /// \return The catenary.
   Catenary3d catenary() const;

src/sagging/stopwatch_sagger.cc

@@ -42,6 +42,15 @@ bool StopwatchSagger::Validate(const bool& is_included_warnings,
   return is_valid;
 }
 
+double StopwatchSagger::VelocityWave() const {
+  // updates class if necessary
+  if ((IsUpdated() == false) && (Update() == false)) {
+    return -999999;
+  }
+
+  return velocity_wave_;
+}
+
 Catenary3d StopwatchSagger::catenary() const {
   return catenary_;
 }

test/sagging/stopwatch_sagger_test.cc

@@ -51,3 +51,11 @@ TEST_F(StopwatchSaggerTest, TimeReturn) {
 TEST_F(StopwatchSaggerTest, Validate) {
   EXPECT_TRUE(s_.Validate(true, nullptr));
 }
+
+TEST_F(StopwatchSaggerTest, VelocityWave) {
+  double value = -999999;
+
+  // checks wave velocity
+  value = s_.VelocityWave();
+  EXPECT_EQ(401.1, helper::Round(value, 1));
+}