diff --git a/reframe/core/buildsystems.py b/reframe/core/buildsystems.py
index ee820c45f7..db16ca3fb5 100644
--- a/reframe/core/buildsystems.py
+++ b/reframe/core/buildsystems.py
@@ -426,8 +426,9 @@ def emit_build_commands(self, environ):
             cmd_parts += [nvcc, *cppflags, *cxxflags, self.srcfile,
                           '-o', executable, *ldflags]
         else:
-            BuildSystemError('could not guess language of file: %s' %
-                             self.srcfile)
+            raise BuildSystemError(
+                f'could not guess language of file: {self.srcfile}'
+            )
 
         return [' '.join(cmd_parts)]
 
diff --git a/unittests/test_buildsystems.py b/unittests/test_buildsystems.py
index 3cf698aaff..fdd2017715 100644
--- a/unittests/test_buildsystems.py
+++ b/unittests/test_buildsystems.py
@@ -235,3 +235,10 @@ def test_compiler_pick(lang):
     }
     assert ([f'{compilers[lang]} {build_system.srcfile} -o foo.x'] ==
             build_system.emit_build_commands(ProgEnvironment('testenv')))
+
+
+def test_singlesource_unknown_language():
+    build_system = bs.SingleSource()
+    build_system.srcfile = 'foo.bar'
+    with pytest.raises(BuildSystemError, match='could not guess language'):
+        build_system.emit_build_commands(ProgEnvironment('testenv'))
diff --git a/unittests/test_pipeline.py b/unittests/test_pipeline.py
index 1e330a072f..b4187fdf35 100644
--- a/unittests/test_pipeline.py
+++ b/unittests/test_pipeline.py
@@ -457,6 +457,21 @@ def __init__(self):
         test.compile()
 
 
+def test_sourcepath_non_existent(local_exec_ctx):
+    @fixtures.custom_prefix('unittests/resources/checks')
+    class MyTest(rfm.CompileOnlyRegressionTest):
+        def __init__(self):
+            self.valid_prog_environs = ['*']
+            self.valid_systems = ['*']
+
+    test = MyTest()
+    test.setup(*local_exec_ctx)
+    test.sourcepath = 'non_existent.c'
+    test.compile()
+    with pytest.raises(BuildError):
+        test.compile_wait()
+
+
 def test_extra_resources(testsys_system):
     @fixtures.custom_prefix('unittests/resources/checks')
     class MyTest(HelloTest):