diff --git a/src/value.cc b/src/value.cc
index ab78c2a0..5ea766c1 100644
--- a/src/value.cc
+++ b/src/value.cc
@@ -363,7 +363,20 @@ std::string Value::toString() const
 			<< ']';
 		break;
 	case NUMBER:
+#ifdef OPENSCAD_TESTING
+		// Quick and dirty hack to work around floating point rounding differences
+		// across platforms for testing purposes.
+	{
+		std::stringstream tmp;
+		tmp.precision(16);
+		tmp << this->num;
+		std::string tmpstr = tmp.str();
+		if (tmpstr.size() > 16) tmpstr.erase(16);
+		stream << tmpstr;
+	}
+#else
 		stream << this->num;
+#endif
 		break;
 	case BOOL:
 		stream << (this->b ? "true" : "false");
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 15f168fe..6de3d938 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -199,6 +199,7 @@ include_directories(${CGAL_INCLUDE_DIRS})
 include_directories(../src)
 
 add_definitions(-DOPENSCAD_VERSION=test -DOPENSCAD_YEAR=2011 -DOPENSCAD_MONTH=10)
+add_definitions(-DOPENSCAD_TESTING)
 
 set(CORE_SOURCES
   tests-common.cc 
diff --git a/tests/regression/echotest/builtin-tests-expected.txt b/tests/regression/echotest/builtin-tests-expected.txt
index e8b2027a..0e8d1a74 100644
--- a/tests/regression/echotest/builtin-tests-expected.txt
+++ b/tests/regression/echotest/builtin-tests-expected.txt
@@ -1 +1 @@
-ECHO: 3.141592653589793
+ECHO: 3.14159265358979
diff --git a/tests/regression/echotest/dim-all-expected.txt b/tests/regression/echotest/dim-all-expected.txt
index 74044a17..d8c32694 100644
--- a/tests/regression/echotest/dim-all-expected.txt
+++ b/tests/regression/echotest/dim-all-expected.txt
@@ -1,16 +1,16 @@
 WARNING: Unsupported DXF Entity `LEADER' (1) in `dim-all.dxf'.
-ECHO: linearX = 51.44957554275265
+ECHO: linearX = 51.4495755427526
 WARNING: Unsupported DXF Entity `LEADER' (1) in `dim-all.dxf'.
-ECHO: linearY = 29.13025467434841
+ECHO: linearY = 29.1302546743484
 WARNING: Unsupported DXF Entity `LEADER' (1) in `dim-all.dxf'.
-ECHO: aligned = 60.00000000000001
+ECHO: aligned = 60.0000000000000
 WARNING: Unsupported DXF Entity `LEADER' (1) in `dim-all.dxf'.
-ECHO: ordinateX = -49.17542445724735
+ECHO: ordinateX = -49.175424457247
 WARNING: Unsupported DXF Entity `LEADER' (1) in `dim-all.dxf'.
-ECHO: ordinateY = 30.86974532565159
+ECHO: ordinateY = 30.8697453256515
 WARNING: Unsupported DXF Entity `LEADER' (1) in `dim-all.dxf'.
 ECHO: radius = 60
 WARNING: Unsupported DXF Entity `LEADER' (1) in `dim-all.dxf'.
 ECHO: diameter = 120
 WARNING: Unsupported DXF Entity `LEADER' (1) in `dim-all.dxf'.
-ECHO: arc = 59.03624346792648
+ECHO: arc = 59.0362434679264