SDC: Add unit test for escaping dollar sign in wire names

Signed-off-by: Tomasz Michalak <tmichalak@antmicro.com>

sdc-plugin/tests/Makefile

diff --git a/sdc-plugin/tests/Makefile b/sdc-plugin/tests/Makefile
index 607b14b..b5f7f96 100644
--- a/sdc-plugin/tests/Makefile
+++ b/sdc-plugin/tests/Makefile
@@ -16,6 +16,8 @@
 	period_check \
 	waveform_check
 
+UNIT_TESTS = escaping
+
 include $(shell pwd)/../../Makefile_test.common
 
 counter_verify = $(call diff_test,counter,sdc) && $(call diff_test,counter,txt)

sdc-plugin/tests/escaping/escaping.test.cc

diff --git a/sdc-plugin/tests/escaping/escaping.test.cc b/sdc-plugin/tests/escaping/escaping.test.cc
new file mode 100644
index 0000000..e17eef6
--- /dev/null
+++ b/sdc-plugin/tests/escaping/escaping.test.cc
@@ -0,0 +1,11 @@
+#include <clocks.h>
+
+#include <gtest/gtest.h>
+
+TEST(ClockTest, EscapeDollarSign) {
+        // convert wire_name to wire_name, i.e. unchanged
+        EXPECT_EQ(Clock::AddEscaping("wire_name"), "wire_name");
+        // convert $wire_name to \$wire_name
+        EXPECT_EQ(Clock::AddEscaping("$wire_name"), "\\$wire_name");
+}
+