Handle unknown namespaces

1 files changed, 15 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/typechecker/NamespaceDependencyLineariserTests.java b/src/test/java/org/shedlang/compiler/typechecker/NamespaceDependencyLineariserTests.java
index fba6d0e4..89283ab9 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/NamespaceDependencyLineariserTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/NamespaceDependencyLineariserTests.java
@@ -4,6 +4,7 @@ import org.junit.jupiter.api.Test;
 import org.shedlang.compiler.ast.untyped.Untyped;
 import org.shedlang.compiler.ast.untyped.UntypedNamespaceNode;
 import org.shedlang.compiler.typechecker.errors.CircularNamespaceDependencyError;
+import org.shedlang.compiler.typechecker.errors.UnknownNamespaceError;
 import org.shedlang.compiler.types.NamespaceName;
 import org.zwobble.precisely.Matcher;
 
@@ -158,6 +159,20 @@ public class NamespaceDependencyLineariserTests {
         ));
     }
 
+    @Test
+    public void whenDependencyIsUnrecognisedThenErrorIsThrown() {
+        var namespaces = List.of(
+            namespaceNode("A", List.of("B"))
+        );
+
+        var error = assertThrows(
+            UnknownNamespaceError.class,
+            () -> NamespaceDependencyLineariser.orderNamespaces(namespaces)
+        );
+
+        assertThat(error.unknownNamespaceName(), equalTo(NamespaceName.of("B")));
+    }
+
     private static UntypedNamespaceNode namespaceNode(
         String namespaceName,
         List<String> dependencies