diff --git a/test/libsolidity/SyntaxTest.cpp b/test/libsolidity/SyntaxTest.cpp
index b2f8015c9..009b3613b 100644
--- a/test/libsolidity/SyntaxTest.cpp
+++ b/test/libsolidity/SyntaxTest.cpp
@@ -113,20 +113,30 @@ void SyntaxTest::parseAndAnalyze()
 
 void SyntaxTest::filterObtainedErrors()
 {
-	string const preamble = "pragma solidity >=0.0;\n// SPDX-License-Identifier: GPL-3.0\n";
 	for (auto const& currentError: filterErrors(compiler().errors(), true))
 	{
 		int locationStart = -1, locationEnd = -1;
 		string sourceName;
 		if (auto location = boost::get_error_info<errinfo_sourceLocation>(*currentError))
 		{
+			solAssert(location->source, "");
+			sourceName = location->source->name();
+
+			solAssert(m_sources.count(sourceName) == 1, "");
+			int preambleSize = static_cast<int>(location->source->source().size()) - static_cast<int>(m_sources[sourceName].size());
+			solAssert(preambleSize >= 0, "");
+
 			// ignore the version & license pragma inserted by the testing tool when calculating locations.
-			if (location->start >= static_cast<int>(preamble.size()))
-				locationStart = location->start - static_cast<int>(preamble.size());
-			if (location->end >= static_cast<int>(preamble.size()))
-				locationEnd = location->end - static_cast<int>(preamble.size());
-			if (location->source)
-				sourceName = location->source->name();
+			if (location->start != -1)
+			{
+				solAssert(location->start >= preambleSize, "");
+				locationStart = location->start - preambleSize;
+			}
+			if (location->end != -1)
+			{
+				solAssert(location->end >= preambleSize, "");
+				locationEnd = location->end - preambleSize;
+			}
 		}
 		m_errorList.emplace_back(SyntaxTestError{
 			currentError->typeName(),
diff --git a/test/libsolidity/syntaxTests/imports/multiple_non_existent_file_names.sol b/test/libsolidity/syntaxTests/imports/multiple_non_existent_file_names.sol
new file mode 100644
index 000000000..4172955ab
--- /dev/null
+++ b/test/libsolidity/syntaxTests/imports/multiple_non_existent_file_names.sol
@@ -0,0 +1,10 @@
+import "~~~some-long-unlikely-file-name-12";
+import "~~~some-long-unlikely-file-name-456";
+import "~~~some-long-unlikely-file-name-7890";
+// This test is here to verify that the license/pragma preamble added by the test suite does not
+// affect source locations in error messages. Positions in messages below should start at 0 and
+// there should be no gaps between the ranges.
+// ----
+// ParserError 6275: (0-44): Source "~~~some-long-unlikely-file-name-12" not found: File not supplied initially.
+// ParserError 6275: (45-90): Source "~~~some-long-unlikely-file-name-456" not found: File not supplied initially.
+// ParserError 6275: (91-137): Source "~~~some-long-unlikely-file-name-7890" not found: File not supplied initially.