From 8210452970eaa2e25c1a1a68318553a11f65b317 Mon Sep 17 00:00:00 2001
From: Bob Nystrom <robert@stuffwithstuff.com>
Date: Sat, 24 Mar 2018 11:10:36 -0700
Subject: [PATCH] Relative imports!

This is a breaking change because existing imports in user Wren code
that assume the path is relative to the entrypoint file will now likely
fail.

Also, stack trace output and host API calls that take a module string
now need the resolved module string, not the short name that appears in
the import.
---
 .../cthulu.wren                               |   0
 .../lovecraft.wren                            |   2 +-
 src/cli/vm.c                                  | 128 ++++++++++--------
 src/include/wren.h                            |  25 ++--
 test/api/call.c                               |   2 +-
 test/api/get_variable.c                       |  10 +-
 test/api/get_variable.wren                    |   2 +-
 test/api/main.c                               |   6 +-
 test/api/reset_stack_after_call_abort.c       |   4 +-
 .../api/reset_stack_after_foreign_construct.c |   4 +-
 test/core/fiber/yield_from_import.wren        |   2 +-
 test/language/foreign/unknown_method.wren     |   2 +-
 .../change_imported_value.wren                |   2 +-
 .../module/compile_error/compile_error.wren   |   2 +-
 test/language/module/cyclic_import/a.wren     |   2 +-
 test/language/module/cyclic_import/b.wren     |   2 +-
 .../module/cyclic_import/cyclic_import.wren   |   2 +-
 .../implicitly_imports_core.wren              |   2 +-
 .../module/inside_block/inside_block.wren     |   2 +-
 test/language/module/missing_for.wren         |   2 +-
 .../module/module_dir/module_dir.wren         |   2 +-
 .../multiple_variables.wren                   |   2 +-
 test/language/module/name_collision.wren      |   2 +-
 test/language/module/newlines/newlines.wren   |   4 +-
 .../module/no_variable/no_variable.wren       |   2 +-
 .../module/relative_import/module_3.wren      |   2 +
 .../relative_import/relative_import.wren      |   8 ++
 .../relative_import/sub/dir/module.wren       |   3 +
 .../relative_import/sub/dir/module_2.wren     |   4 +
 .../module/relative_import/sub/module.wren    |   3 +
 .../module/relative_import/sub/module_2.wren  |   2 +
 .../module/relative_import/sub/module_3.wren  |   2 +
 test/language/module/shared_import/a.wren     |   2 +-
 test/language/module/shared_import/b.wren     |   2 +-
 .../module/shared_import/shared_import.wren   |   4 +-
 .../module/simple_import/simple_import.wren   |   2 +-
 test/language/module/unknown_module.wren      |   2 +-
 .../unknown_variable/unknown_variable.wren    |   2 +-
 test/meta/get_module_variables.wren           |   2 +-
 util/benchmark.py                             |   2 +-
 util/test.py                                  |   2 +-
 41 files changed, 152 insertions(+), 107 deletions(-)
 rename example/{import-module => import_module}/cthulu.wren (100%)
 rename example/{import-module => import_module}/lovecraft.wren (79%)
 create mode 100644 test/language/module/relative_import/module_3.wren
 create mode 100644 test/language/module/relative_import/relative_import.wren
 create mode 100644 test/language/module/relative_import/sub/dir/module.wren
 create mode 100644 test/language/module/relative_import/sub/dir/module_2.wren
 create mode 100644 test/language/module/relative_import/sub/module.wren
 create mode 100644 test/language/module/relative_import/sub/module_2.wren
 create mode 100644 test/language/module/relative_import/sub/module_3.wren

diff --git a/example/import-module/cthulu.wren b/example/import_module/cthulu.wren
similarity index 100%
rename from example/import-module/cthulu.wren
rename to example/import_module/cthulu.wren
diff --git a/example/import-module/lovecraft.wren b/example/import_module/lovecraft.wren
similarity index 79%
rename from example/import-module/lovecraft.wren
rename to example/import_module/lovecraft.wren
index 57b11331..08e46ad5 100644
--- a/example/import-module/lovecraft.wren
+++ b/example/import_module/lovecraft.wren
@@ -1,4 +1,4 @@
-import "cthulu" for Cthulu
+import "./cthulu" for Cthulu
 
 class Lovecraft {
   construct new() {}
diff --git a/src/cli/vm.c b/src/cli/vm.c
index 05f2b2fd..863e85e6 100644
--- a/src/cli/vm.c
+++ b/src/cli/vm.c
@@ -3,6 +3,7 @@
 
 #include "io.h"
 #include "modules.h"
+#include "path.h"
 #include "scheduler.h"
 #include "vm.h"
 
@@ -15,7 +16,9 @@ static WrenForeignMethodFn afterLoadFn = NULL;
 
 static uv_loop_t* loop;
 
-static char const* rootDirectory = NULL;
+// TODO: This isn't currently used, but probably will be when package imports
+// are supported. If not then, then delete this.
+static char* rootDirectory = NULL;
 
 // The exit code to use unless some other error overrides it.
 int defaultExitCode = 0;
@@ -44,7 +47,7 @@ static char* readFile(const char* path)
   }
   
   // Read the entire file.
-  size_t bytesRead = fread(buffer, sizeof(char), fileSize, file);
+  size_t bytesRead = fread(buffer, 1, fileSize, file);
   if (bytesRead < fileSize)
   {
     fprintf(stderr, "Could not read file \"%s\".\n", path);
@@ -58,25 +61,46 @@ static char* readFile(const char* path)
   return buffer;
 }
 
-// Converts the module [name] to a file path.
-static char* wrenFilePath(const char* name)
+// Applies the CLI's import resolution policy. The rules are:
+//
+// * If [name] starts with "./" or "../", it is a relative import, relative to
+//   [importer]. The resolved path is [name] concatenated onto the directory
+//   containing [importer] and then normalized.
+//
+//   For example, importing "./a/./b/../c" from "d/e/f" gives you "d/e/a/c".
+//
+// * Otherwise, it is a "package" import. This isn't implemented yet.
+//
+static const char* resolveModule(WrenVM* vm, const char* importer,
+                                 const char* name)
 {
-  // The module path is relative to the root directory and with ".wren".
-  size_t rootLength = rootDirectory == NULL ? 0 : strlen(rootDirectory);
   size_t nameLength = strlen(name);
-  size_t pathLength = rootLength + nameLength + 5;
-  char* path = (char*)malloc(pathLength + 1);
   
-  if (rootDirectory != NULL)
+  // See if it's a relative import.
+  if (nameLength > 2 &&
+      ((name[0] == '.' && name[1] == '/') ||
+       (name[0] == '.' && name[1] == '.' && name[2] == '/')))
   {
-    memcpy(path, rootDirectory, rootLength);
+    // Get the directory containing the importing module.
+    Path* relative = pathNew(importer);
+    pathDirName(relative);
+    
+    // Add the relative import path.
+    pathJoin(relative, name);
+    Path* normal = pathNormalize(relative);
+    pathFree(relative);
+
+    char* resolved = pathToString(normal);
+    pathFree(normal);
+    return resolved;
+  }
+  else
+  {
+    // TODO: Implement package imports. For now, treat any non-relative import
+    // as an import relative to the current working directory.
   }
   
-  memcpy(path + rootLength, name, nameLength);
-  memcpy(path + rootLength + nameLength, ".wren", 5);
-  path[pathLength] = '\0';
-  
-  return path;
+  return name;
 }
 
 // Attempts to read the source for [module] relative to the current root
@@ -86,32 +110,26 @@ static char* wrenFilePath(const char* name)
 // module was found but could not be read.
 static char* readModule(WrenVM* vm, const char* module)
 {
-  char* source = readBuiltInModule(module);
+  // Since the module has already been resolved, it should now be either a
+  // valid relative path, or a package-style name.
+  
+  // TODO: Implement package imports.
+  
+  // Add a ".wren" file extension.
+  Path* modulePath = pathNew(module);
+  pathAppendString(modulePath, ".wren");
+  
+  char* source = readFile(modulePath->chars);
+  pathFree(modulePath);
+  
   if (source != NULL) return source;
-  
-  // First try to load the module with a ".wren" extension.
-  char* modulePath = wrenFilePath(module);
-  char* moduleContents = readFile(modulePath);
-  free(modulePath);
-  
-  if (moduleContents != NULL) return moduleContents;
-  
-  // If no contents could be loaded treat the module name as specifying a
-  // directory and try to load the "module.wren" file in the directory.
-  size_t moduleLength = strlen(module);
-  size_t moduleDirLength = moduleLength + 7;
-  char* moduleDir = (char*)malloc(moduleDirLength + 1);
-  memcpy(moduleDir, module, moduleLength);
-  memcpy(moduleDir + moduleLength, "/module", 7);
-  moduleDir[moduleDirLength] = '\0';
-  
-  char* moduleDirPath = wrenFilePath(moduleDir);
-  free(moduleDir);
-  
-  moduleContents = readFile(moduleDirPath);
-  free(moduleDirPath);
-  
-  return moduleContents;
+
+  // TODO: This used to look for a file named "<path>/module.wren" if
+  // "<path>.wren" could not be found. Do we still want to support that with
+  // the new relative import and package stuff?
+
+  // Otherwise, see if it's a built-in module.
+  return readBuiltInModule(module);
 }
 
 // Binds foreign methods declared in either built in modules, or the injected
@@ -179,6 +197,7 @@ static void initVM()
 
   config.bindForeignMethodFn = bindForeignMethod;
   config.bindForeignClassFn = bindForeignClass;
+  config.resolveModuleFn = resolveModule;
   config.loadModuleFn = readModule;
   config.writeFn = write;
   config.errorFn = reportError;
@@ -207,18 +226,6 @@ static void freeVM()
 
 void runFile(const char* path)
 {
-  // Use the directory where the file is as the root to resolve imports
-  // relative to.
-  char* root = NULL;
-  const char* lastSlash = strrchr(path, '/');
-  if (lastSlash != NULL)
-  {
-    root = (char*)malloc(lastSlash - path + 2);
-    memcpy(root, path, lastSlash - path + 1);
-    root[lastSlash - path + 1] = '\0';
-    rootDirectory = root;
-  }
-
   char* source = readFile(path);
   if (source == NULL)
   {
@@ -226,9 +233,19 @@ void runFile(const char* path)
     exit(66);
   }
 
+  // Use the directory where the file is as the root to resolve imports
+  // relative to.
+  Path* directory = pathNew(path);
+  pathDirName(directory);
+  rootDirectory = pathToString(directory);
+  pathFree(directory);
+  
+  Path* moduleName = pathNew(path);
+  pathRemoveExtension(moduleName);
+
   initVM();
 
-  WrenInterpretResult result = wrenInterpret(vm, "main", source);
+  WrenInterpretResult result = wrenInterpret(vm, moduleName->chars, source);
 
   if (afterLoadFn != NULL) afterLoadFn(vm);
   
@@ -240,7 +257,8 @@ void runFile(const char* path)
   freeVM();
 
   free(source);
-  free(root);
+  free(rootDirectory);
+  pathFree(moduleName);
 
   // Exit with an error code if the script failed.
   if (result == WREN_RESULT_COMPILE_ERROR) exit(65); // EX_DATAERR.
@@ -256,7 +274,7 @@ int runRepl()
   printf("\\\\/\"-\n");
   printf(" \\_/   wren v%s\n", WREN_VERSION_STRING);
 
-  wrenInterpret(vm, "main", "import \"repl\"\n");
+  wrenInterpret(vm, "repl", "import \"repl\"\n");
   
   uv_run(loop, UV_RUN_DEFAULT);
 
diff --git a/src/include/wren.h b/src/include/wren.h
index 09a3aa15..dbea3077 100644
--- a/src/include/wren.h
+++ b/src/include/wren.h
@@ -92,14 +92,15 @@ typedef enum
 // Reports an error to the user.
 //
 // An error detected during compile time is reported by calling this once with
-// `WREN_ERROR_COMPILE`, the name of the module and line where the error occurs,
-// and the compiler's error message.
+// [type] `WREN_ERROR_COMPILE`, the resolved name of the [module] and [line]
+// where the error occurs, and the compiler's error [message].
 //
-// A runtime error is reported by calling this once with `WREN_ERROR_RUNTIME`,
-// no module or line, and the runtime error's message. After that, a series of
-// `WREN_ERROR_STACK_TRACE` calls are made for each line in the stack trace.
-// Each of those has the module and line where the method or function is
-// defined and [message] is the name of the method or function.
+// A runtime error is reported by calling this once with [type]
+// `WREN_ERROR_RUNTIME`, no [module] or [line], and the runtime error's
+// [message]. After that, a series of [type] `WREN_ERROR_STACK_TRACE` calls are
+// made for each line in the stack trace. Each of those has the resolved
+// [module] and [line] where the method or function is defined and [message] is
+// the name of the method or function.
 typedef void (*WrenErrorFn)(
     WrenVM* vm, WrenErrorType type, const char* module, int line,
     const char* message);
@@ -120,7 +121,7 @@ typedef struct
 } WrenForeignClassMethods;
 
 // Returns a pair of pointers to the foreign methods used to allocate and
-// finalize the data for instances of [className] in [module].
+// finalize the data for instances of [className] in resolved [module].
 typedef WrenForeignClassMethods (*WrenBindForeignClassFn)(
     WrenVM* vm, const char* module, const char* className);
 
@@ -287,7 +288,8 @@ void wrenFreeVM(WrenVM* vm);
 // Immediately run the garbage collector to free unused memory.
 void wrenCollectGarbage(WrenVM* vm);
 
-// Runs [source], a string of Wren source code in a new fiber in [vm].
+// Runs [source], a string of Wren source code in a new fiber in [vm] in the
+// context of resolved [module].
 WrenInterpretResult wrenInterpret(WrenVM* vm, const char* module,
                                   const char* source);
 
@@ -468,10 +470,11 @@ void wrenGetListElement(WrenVM* vm, int listSlot, int index, int elementSlot);
 // an element, use `-1` for the index.
 void wrenInsertInList(WrenVM* vm, int listSlot, int index, int elementSlot);
 
-// Looks up the top level variable with [name] in [module] and stores it in
-// [slot].
+// Looks up the top level variable with [name] in resolved [module] and stores
+// it in [slot].
 void wrenGetVariable(WrenVM* vm, const char* module, const char* name,
                      int slot);
+
 // Sets the current fiber to be aborted, and uses the value in [slot] as the
 // runtime error object.
 void wrenAbortFiber(WrenVM* vm, int slot);
diff --git a/test/api/call.c b/test/api/call.c
index 8dadcc35..7f4264e2 100644
--- a/test/api/call.c
+++ b/test/api/call.c
@@ -6,7 +6,7 @@
 void callRunTests(WrenVM* vm)
 {
   wrenEnsureSlots(vm, 1);
-  wrenGetVariable(vm, "main", "Call", 0);
+  wrenGetVariable(vm, "test/api/call", "Call", 0);
   WrenHandle* callClass = wrenGetSlotHandle(vm, 0);
   
   WrenHandle* noParams = wrenMakeCallHandle(vm, "noParams");
diff --git a/test/api/get_variable.c b/test/api/get_variable.c
index c5237214..5dece4cf 100644
--- a/test/api/get_variable.c
+++ b/test/api/get_variable.c
@@ -4,23 +4,23 @@
 
 static void beforeDefined(WrenVM* vm)
 {
-  wrenGetVariable(vm, "main", "A", 0);
+  wrenGetVariable(vm, "test/api/get_variable", "A", 0);
 }
 
 static void afterDefined(WrenVM* vm)
 {
-  wrenGetVariable(vm, "main", "A", 0);
+  wrenGetVariable(vm, "test/api/get_variable", "A", 0);
 }
 
 static void afterAssigned(WrenVM* vm)
 {
-  wrenGetVariable(vm, "main", "A", 0);
+  wrenGetVariable(vm, "test/api/get_variable", "A", 0);
 }
 
 static void otherSlot(WrenVM* vm)
 {
   wrenEnsureSlots(vm, 3);
-  wrenGetVariable(vm, "main", "B", 2);
+  wrenGetVariable(vm, "test/api/get_variable", "B", 2);
   
   // Move it into return position.
   const char* string = wrenGetSlotString(vm, 2);
@@ -29,7 +29,7 @@ static void otherSlot(WrenVM* vm)
 
 static void otherModule(WrenVM* vm)
 {
-  wrenGetVariable(vm, "get_variable_module", "Variable", 0);
+  wrenGetVariable(vm, "test/api/get_variable_module", "Variable", 0);
 }
 
 WrenForeignMethodFn getVariableBindMethod(const char* signature)
diff --git a/test/api/get_variable.wren b/test/api/get_variable.wren
index 89b92e4b..48cdf84c 100644
--- a/test/api/get_variable.wren
+++ b/test/api/get_variable.wren
@@ -1,4 +1,4 @@
-import "get_variable_module"
+import "./get_variable_module"
 
 class GetVariable {
   foreign static beforeDefined()
diff --git a/test/api/main.c b/test/api/main.c
index ed3510d2..52610afa 100644
--- a/test/api/main.c
+++ b/test/api/main.c
@@ -24,8 +24,8 @@ const char* testName;
 static WrenForeignMethodFn bindForeignMethod(
     WrenVM* vm, const char* module, const char* className,
     bool isStatic, const char* signature)
-{  
-  if (strcmp(module, "main") != 0) return NULL;
+{
+  if (strncmp(module, "test/", 5) != 0) return NULL;
 
   // For convenience, concatenate all of the method qualifiers into a single
   // signature string.
@@ -78,7 +78,7 @@ static WrenForeignClassMethods bindForeignClass(
     WrenVM* vm, const char* module, const char* className)
 {
   WrenForeignClassMethods methods = { NULL, NULL };
-  if (strcmp(module, "main") != 0) return methods;
+  if (strncmp(module, "test/", 5) != 0) return methods;
 
   foreignClassBindClass(className, &methods);
   if (methods.allocate != NULL) return methods;
diff --git a/test/api/reset_stack_after_call_abort.c b/test/api/reset_stack_after_call_abort.c
index 8136796e..c94687fe 100644
--- a/test/api/reset_stack_after_call_abort.c
+++ b/test/api/reset_stack_after_call_abort.c
@@ -6,7 +6,7 @@
 void resetStackAfterCallAbortRunTests(WrenVM* vm)
 {
   wrenEnsureSlots(vm, 1);
-  wrenGetVariable(vm, "main", "Test", 0);
+  wrenGetVariable(vm, "test/api/reset_stack_after_call_abort", "Test", 0);
   WrenHandle* testClass = wrenGetSlotHandle(vm, 0);
   
   WrenHandle* abortFiber = wrenMakeCallHandle(vm, "abortFiber()");
@@ -25,4 +25,4 @@ void resetStackAfterCallAbortRunTests(WrenVM* vm)
   wrenReleaseHandle(vm, testClass);
   wrenReleaseHandle(vm, abortFiber);
   wrenReleaseHandle(vm, afterConstruct);
-}
\ No newline at end of file
+}
diff --git a/test/api/reset_stack_after_foreign_construct.c b/test/api/reset_stack_after_foreign_construct.c
index f24783d8..ce829a8b 100644
--- a/test/api/reset_stack_after_foreign_construct.c
+++ b/test/api/reset_stack_after_foreign_construct.c
@@ -22,7 +22,7 @@ void resetStackAfterForeignConstructBindClass(
 void resetStackAfterForeignConstructRunTests(WrenVM* vm)
 {
   wrenEnsureSlots(vm, 1);
-  wrenGetVariable(vm, "main", "Test", 0);
+  wrenGetVariable(vm, "test/api/reset_stack_after_foreign_construct", "Test", 0);
   WrenHandle* testClass = wrenGetSlotHandle(vm, 0);
   
   WrenHandle* callConstruct = wrenMakeCallHandle(vm, "callConstruct()");
@@ -41,4 +41,4 @@ void resetStackAfterForeignConstructRunTests(WrenVM* vm)
   wrenReleaseHandle(vm, testClass);
   wrenReleaseHandle(vm, callConstruct);
   wrenReleaseHandle(vm, afterConstruct);
-}
\ No newline at end of file
+}
diff --git a/test/core/fiber/yield_from_import.wren b/test/core/fiber/yield_from_import.wren
index dbb0e77d..80062e9d 100644
--- a/test/core/fiber/yield_from_import.wren
+++ b/test/core/fiber/yield_from_import.wren
@@ -1,7 +1,7 @@
 var fiber = Fiber.new {
   System.print("fiber 1")
 
-  import "yield_from_import_module"
+  import "./yield_from_import_module"
 
   System.print("fiber 2")
 }
diff --git a/test/language/foreign/unknown_method.wren b/test/language/foreign/unknown_method.wren
index 9b7c7c45..2cdf01be 100644
--- a/test/language/foreign/unknown_method.wren
+++ b/test/language/foreign/unknown_method.wren
@@ -1,3 +1,3 @@
 class Foo {
-  foreign someUnknownMethod // expect runtime error: Could not find foreign method 'someUnknownMethod' for class Foo in module 'main'.
+  foreign someUnknownMethod // expect runtime error: Could not find foreign method 'someUnknownMethod' for class Foo in module 'test/language/foreign/unknown_method'.
 }
diff --git a/test/language/module/change_imported_value/change_imported_value.wren b/test/language/module/change_imported_value/change_imported_value.wren
index 0f5aa0ff..1f7bc986 100644
--- a/test/language/module/change_imported_value/change_imported_value.wren
+++ b/test/language/module/change_imported_value/change_imported_value.wren
@@ -1,4 +1,4 @@
-import "module" for Module, Other
+import "./module" for Module, Other
 
 System.print(Module) // expect: before
 
diff --git a/test/language/module/compile_error/compile_error.wren b/test/language/module/compile_error/compile_error.wren
index 86141630..f136e882 100644
--- a/test/language/module/compile_error/compile_error.wren
+++ b/test/language/module/compile_error/compile_error.wren
@@ -1,2 +1,2 @@
 System.print("before") // expect: before
-import "module" for Module // expect runtime error: Could not compile module 'module'.
+import "./module" for Module // expect runtime error: Could not compile module 'test/language/module/compile_error/module'.
diff --git a/test/language/module/cyclic_import/a.wren b/test/language/module/cyclic_import/a.wren
index c2806adb..68fda993 100644
--- a/test/language/module/cyclic_import/a.wren
+++ b/test/language/module/cyclic_import/a.wren
@@ -3,7 +3,7 @@ System.print("start a")
 
 var A = "a value"
 System.print("a defined %(A)")
-import "b" for B
+import "./b" for B
 System.print("a imported %(B)")
 
 System.print("end a")
diff --git a/test/language/module/cyclic_import/b.wren b/test/language/module/cyclic_import/b.wren
index 21fb44ae..968b4d26 100644
--- a/test/language/module/cyclic_import/b.wren
+++ b/test/language/module/cyclic_import/b.wren
@@ -3,7 +3,7 @@ System.print("start b")
 
 var B = "b value"
 System.print("b defined %(B)")
-import "a" for A
+import "./a" for A
 System.print("b imported %(A)")
 
 System.print("end b")
diff --git a/test/language/module/cyclic_import/cyclic_import.wren b/test/language/module/cyclic_import/cyclic_import.wren
index 1cb4de97..afd67b35 100644
--- a/test/language/module/cyclic_import/cyclic_import.wren
+++ b/test/language/module/cyclic_import/cyclic_import.wren
@@ -1,4 +1,4 @@
-import "a"
+import "./a"
 
 // Shared module should only run once:
 // expect: start a
diff --git a/test/language/module/implicitly_imports_core/implicitly_imports_core.wren b/test/language/module/implicitly_imports_core/implicitly_imports_core.wren
index 1fef7723..e36dc794 100644
--- a/test/language/module/implicitly_imports_core/implicitly_imports_core.wren
+++ b/test/language/module/implicitly_imports_core/implicitly_imports_core.wren
@@ -1,4 +1,4 @@
-import "module"
+import "./module"
 // expect: Bool
 // expect: Class
 // expect: Fiber
diff --git a/test/language/module/inside_block/inside_block.wren b/test/language/module/inside_block/inside_block.wren
index f19bc0c7..27742004 100644
--- a/test/language/module/inside_block/inside_block.wren
+++ b/test/language/module/inside_block/inside_block.wren
@@ -1,7 +1,7 @@
 var Module = "outer"
 
 if (true) {
-  import "module" for Module
+  import "./module" for Module
   // expect: ran module
 
   System.print(Module) // expect: from module
diff --git a/test/language/module/missing_for.wren b/test/language/module/missing_for.wren
index 7de00259..1c0153f3 100644
--- a/test/language/module/missing_for.wren
+++ b/test/language/module/missing_for.wren
@@ -1 +1 @@
-import "module" NoString // expect error
+import "./module" NoString // expect error
diff --git a/test/language/module/module_dir/module_dir.wren b/test/language/module/module_dir/module_dir.wren
index e2867d02..a2c56349 100644
--- a/test/language/module/module_dir/module_dir.wren
+++ b/test/language/module/module_dir/module_dir.wren
@@ -1,3 +1,3 @@
-import "something" for Index
+import "./something/module" for Index
 
 System.print(Index) // expect: index
\ No newline at end of file
diff --git a/test/language/module/multiple_variables/multiple_variables.wren b/test/language/module/multiple_variables/multiple_variables.wren
index abf387c6..50c05bd8 100644
--- a/test/language/module/multiple_variables/multiple_variables.wren
+++ b/test/language/module/multiple_variables/multiple_variables.wren
@@ -1,4 +1,4 @@
-import "module" for Module1, Module2, Module3, Module4, Module5
+import "./module" for Module1, Module2, Module3, Module4, Module5
 
 // Only execute module body once:
 // expect: ran module
diff --git a/test/language/module/name_collision.wren b/test/language/module/name_collision.wren
index 468c2448..d36cec5f 100644
--- a/test/language/module/name_collision.wren
+++ b/test/language/module/name_collision.wren
@@ -1,2 +1,2 @@
 var Collides
-import "module" for Collides // expect error
+import "./module" for Collides // expect error
diff --git a/test/language/module/newlines/newlines.wren b/test/language/module/newlines/newlines.wren
index 559ce949..947a0b8c 100644
--- a/test/language/module/newlines/newlines.wren
+++ b/test/language/module/newlines/newlines.wren
@@ -1,9 +1,9 @@
 import
 
 
-"module"
+"./module"
 
-import "module" for
+import "./module" for
 
 A,
 
diff --git a/test/language/module/no_variable/no_variable.wren b/test/language/module/no_variable/no_variable.wren
index 38b440d3..d88b47e3 100644
--- a/test/language/module/no_variable/no_variable.wren
+++ b/test/language/module/no_variable/no_variable.wren
@@ -1,2 +1,2 @@
-import "module"
+import "./module"
 // expect: ran module
diff --git a/test/language/module/relative_import/module_3.wren b/test/language/module/relative_import/module_3.wren
new file mode 100644
index 00000000..a80f3ce9
--- /dev/null
+++ b/test/language/module/relative_import/module_3.wren
@@ -0,0 +1,2 @@
+// nontest
+System.print("module_3")
diff --git a/test/language/module/relative_import/relative_import.wren b/test/language/module/relative_import/relative_import.wren
new file mode 100644
index 00000000..6cff529a
--- /dev/null
+++ b/test/language/module/relative_import/relative_import.wren
@@ -0,0 +1,8 @@
+import "./sub/module"
+import "./sub/././///dir/module"
+// expect: sub/module
+// expect: sub/module_2
+// expect: sub/dir/module
+// expect: sub/dir/module_2
+// expect: sub/module_3
+// expect: module_3
diff --git a/test/language/module/relative_import/sub/dir/module.wren b/test/language/module/relative_import/sub/dir/module.wren
new file mode 100644
index 00000000..99390971
--- /dev/null
+++ b/test/language/module/relative_import/sub/dir/module.wren
@@ -0,0 +1,3 @@
+// nontest
+System.print("sub/dir/module")
+import "./module_2"
diff --git a/test/language/module/relative_import/sub/dir/module_2.wren b/test/language/module/relative_import/sub/dir/module_2.wren
new file mode 100644
index 00000000..ef03e323
--- /dev/null
+++ b/test/language/module/relative_import/sub/dir/module_2.wren
@@ -0,0 +1,4 @@
+// nontest
+System.print("sub/dir/module_2")
+import "../module_3"
+import "../../module_3"
diff --git a/test/language/module/relative_import/sub/module.wren b/test/language/module/relative_import/sub/module.wren
new file mode 100644
index 00000000..89263f7e
--- /dev/null
+++ b/test/language/module/relative_import/sub/module.wren
@@ -0,0 +1,3 @@
+// nontest
+System.print("sub/module")
+import "./module_2"
diff --git a/test/language/module/relative_import/sub/module_2.wren b/test/language/module/relative_import/sub/module_2.wren
new file mode 100644
index 00000000..24af1ed7
--- /dev/null
+++ b/test/language/module/relative_import/sub/module_2.wren
@@ -0,0 +1,2 @@
+// nontest
+System.print("sub/module_2")
diff --git a/test/language/module/relative_import/sub/module_3.wren b/test/language/module/relative_import/sub/module_3.wren
new file mode 100644
index 00000000..cb62156c
--- /dev/null
+++ b/test/language/module/relative_import/sub/module_3.wren
@@ -0,0 +1,2 @@
+// nontest
+System.print("sub/module_3")
diff --git a/test/language/module/shared_import/a.wren b/test/language/module/shared_import/a.wren
index 6478e5a7..7aa918df 100644
--- a/test/language/module/shared_import/a.wren
+++ b/test/language/module/shared_import/a.wren
@@ -1,5 +1,5 @@
 // nontest
 System.print("a")
-import "shared" for Shared
+import "./shared" for Shared
 var A = "a %(Shared)"
 System.print("a done")
diff --git a/test/language/module/shared_import/b.wren b/test/language/module/shared_import/b.wren
index 9449134f..0317bf58 100644
--- a/test/language/module/shared_import/b.wren
+++ b/test/language/module/shared_import/b.wren
@@ -1,5 +1,5 @@
 // nontest
 System.print("b")
-import "shared" for Shared
+import "./shared" for Shared
 var B = "b %(Shared)"
 System.print("b done")
diff --git a/test/language/module/shared_import/shared_import.wren b/test/language/module/shared_import/shared_import.wren
index 970cfe62..9324b25d 100644
--- a/test/language/module/shared_import/shared_import.wren
+++ b/test/language/module/shared_import/shared_import.wren
@@ -1,5 +1,5 @@
-import "a" for A
-import "b" for B
+import "./a" for A
+import "./b" for B
 
 // Shared module should only run once:
 // expect: a
diff --git a/test/language/module/simple_import/simple_import.wren b/test/language/module/simple_import/simple_import.wren
index eb46932b..67764c32 100644
--- a/test/language/module/simple_import/simple_import.wren
+++ b/test/language/module/simple_import/simple_import.wren
@@ -1,4 +1,4 @@
-import "module" for Module
+import "./module" for Module
 // expect: ran module
 
 System.print(Module) // expect: from module
diff --git a/test/language/module/unknown_module.wren b/test/language/module/unknown_module.wren
index 6b096cb2..a80cc297 100644
--- a/test/language/module/unknown_module.wren
+++ b/test/language/module/unknown_module.wren
@@ -1 +1 @@
-import "does_not_exist" for DoesNotExist // expect runtime error: Could not load module 'does_not_exist'.
+import "./does_not_exist" for DoesNotExist // expect runtime error: Could not load module 'test/language/module/does_not_exist'.
diff --git a/test/language/module/unknown_variable/unknown_variable.wren b/test/language/module/unknown_variable/unknown_variable.wren
index 12029e5e..23f347c9 100644
--- a/test/language/module/unknown_variable/unknown_variable.wren
+++ b/test/language/module/unknown_variable/unknown_variable.wren
@@ -1,3 +1,3 @@
 // Should execute the module:
 // expect: ran module
-import "module" for DoesNotExist // expect runtime error: Could not find a variable named 'DoesNotExist' in module 'module'.
+import "./module" for DoesNotExist // expect runtime error: Could not find a variable named 'DoesNotExist' in module 'test/language/module/unknown_variable/module'.
diff --git a/test/meta/get_module_variables.wren b/test/meta/get_module_variables.wren
index c5ab61b9..34dc6a7d 100644
--- a/test/meta/get_module_variables.wren
+++ b/test/meta/get_module_variables.wren
@@ -1,6 +1,6 @@
 import "meta" for Meta
 
-var variables = Meta.getModuleVariables("main")
+var variables = Meta.getModuleVariables("test/meta/get_module_variables")
 
 // Includes implicitly imported core stuff.
 System.print(variables.contains("Object")) // expect: true
diff --git a/util/benchmark.py b/util/benchmark.py
index 612bbea9..f21e1979 100755
--- a/util/benchmark.py
+++ b/util/benchmark.py
@@ -40,7 +40,7 @@ import sys
 
 WREN_DIR = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
 WREN_BIN = os.path.join(WREN_DIR, 'bin')
-BENCHMARK_DIR = os.path.join(WREN_DIR, 'test', 'benchmark')
+BENCHMARK_DIR = os.path.join('test', 'benchmark')
 
 # How many times to run a given benchmark.
 NUM_TRIALS = 10
diff --git a/util/test.py b/util/test.py
index dac46ad5..adfa9b62 100755
--- a/util/test.py
+++ b/util/test.py
@@ -32,7 +32,7 @@ EXPECT_ERROR_PATTERN = re.compile(r'// expect error(?! line)')
 EXPECT_ERROR_LINE_PATTERN = re.compile(r'// expect error line (\d+)')
 EXPECT_RUNTIME_ERROR_PATTERN = re.compile(r'// expect (handled )?runtime error: (.+)')
 ERROR_PATTERN = re.compile(r'\[.* line (\d+)\] Error')
-STACK_TRACE_PATTERN = re.compile(r'\[main line (\d+)\] in')
+STACK_TRACE_PATTERN = re.compile(r'\[test/.* line (\d+)\] in')
 STDIN_PATTERN = re.compile(r'// stdin: (.*)')
 SKIP_PATTERN = re.compile(r'// skip: (.*)')
 NONTEST_PATTERN = re.compile(r'// nontest')