diff --git a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_test.go b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_test.go
index a28a4833ca..ee063c7aa9 100644
--- a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_test.go
+++ b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_test.go
@@ -20,10 +20,10 @@ func (suite *KurtosisTypeConstructorTestSuite) TestImageBuildSpecTest() {
 	suite.packageContentProvider.EXPECT().
 		GetAbsoluteLocator(testModulePackageId, testModuleMainFileLocator, testBuildContextDir, testNoPackageReplaceOptions).
 		Times(1).
-		Return(testBuildContextLocator, nil)
+		Return(testBuildContextAbsoluteLocator, nil)
 
 	suite.packageContentProvider.EXPECT().
-		GetOnDiskAbsolutePackageFilePath(testContainerImageLocator).
+		GetOnDiskAbsolutePackageFilePath(testContainerImageAbsoluteLocator).
 		Times(1).
 		Return(testOnDiskContainerImagePath, nil)
 
diff --git a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_with_build_file.go b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_with_build_file_test.go
similarity index 92%
rename from core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_with_build_file.go
rename to core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_with_build_file_test.go
index c07bd5d40c..042d81d601 100644
--- a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_with_build_file.go
+++ b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_with_build_file_test.go
@@ -20,10 +20,10 @@ func (suite *KurtosisTypeConstructorTestSuite) TestImageBuildSpecTestWithBuildFi
 	suite.packageContentProvider.EXPECT().
 		GetAbsoluteLocator(testModulePackageId, testModuleMainFileLocator, testBuildContextDir, testNoPackageReplaceOptions).
 		Times(1).
-		Return(testBuildContextLocator, nil)
+		Return(testModulePackageAbsoluteLocator, nil)
 
 	suite.packageContentProvider.EXPECT().
-		GetOnDiskAbsolutePackageFilePath(testContainerImageLocatorWithBuildFile).
+		GetOnDiskAbsolutePackageFilePath(testContainerImageAbsoluteLocatorWithBuildFile).
 		Times(1).
 		Return(testOnDiskContainerImagePathWithBuildFile, nil)
 
@@ -56,5 +56,4 @@ func (t *imageBuildSpecWithBuildFileTest) Assert(typeValue builtin_argument.Kurt
 	require.Nil(t, err)
 	require.Equal(t, testOnDiskContainerImagePathWithBuildFile, imageBuildSpec.GetContainerImageFilePath())
 	require.Equal(t, testOnDiskContextDirPath, imageBuildSpec.GetBuildContextDir())
-	//require.Equal(t, "", imageBuildSpec.GetTargetStage())
 }
diff --git a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_with_target_stage_test.go b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_with_target_stage_test.go
index bd46adf480..5bd7beb892 100644
--- a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_with_target_stage_test.go
+++ b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/image_build_spec_framework_with_target_stage_test.go
@@ -20,10 +20,10 @@ func (suite *KurtosisTypeConstructorTestSuite) TestImageBuildSpecWithTargetStage
 	suite.packageContentProvider.EXPECT().
 		GetAbsoluteLocator(testModulePackageId, testModuleMainFileLocator, testBuildContextDir, testNoPackageReplaceOptions).
 		Times(1).
-		Return(testBuildContextLocator, nil)
+		Return(testModulePackageAbsoluteLocator, nil)
 
 	suite.packageContentProvider.EXPECT().
-		GetOnDiskAbsolutePackageFilePath(testContainerImageLocator).
+		GetOnDiskAbsolutePackageFilePath(testContainerImageAbsoluteLocator).
 		Times(1).
 		Return(testOnDiskContainerImagePath, nil)
 
diff --git a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/import_module_framework_test.go b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/import_module_framework_test.go
index 7c098a53d3..3ae1fff47d 100644
--- a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/import_module_framework_test.go
+++ b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/import_module_framework_test.go
@@ -38,7 +38,7 @@ func (suite *KurtosisHelperTestSuite) TestImportFile() {
 	// start with an empty cache to validate it gets populated
 	moduleGlobalCache := map[string]*startosis_packages.ModuleCacheEntry{}
 
-	suite.packageContentProvider.EXPECT().GetModuleContents(testModuleFileName).Return("Hello World!", nil)
+	suite.packageContentProvider.EXPECT().GetModuleContents(testModuleAbsoluteLocator).Return("Hello World!", nil)
 	suite.packageContentProvider.EXPECT().GetAbsoluteLocator(testModulePackageId, startosis_constants.PackageIdPlaceholderForStandaloneScript, testModuleRelativeLocator, testNoPackageReplaceOptions).Return(testModuleAbsoluteLocator, nil)
 
 	suite.run(&importModuleTestCase{
diff --git a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/nix_build_spec_framework_test.go b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/nix_build_spec_framework_test.go
index f4c5909dd2..b15c184811 100644
--- a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/nix_build_spec_framework_test.go
+++ b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/nix_build_spec_framework_test.go
@@ -20,15 +20,15 @@ func (suite *KurtosisTypeConstructorTestSuite) TestNixBuildSpecTest() {
 	suite.packageContentProvider.EXPECT().
 		GetAbsoluteLocator(testModulePackageId, testModuleMainFileLocator, testBuildContextDir, testNoPackageReplaceOptions).
 		Times(1).
-		Return(testBuildContextLocator, nil)
+		Return(testModulePackageAbsoluteLocator, nil)
 
 	suite.packageContentProvider.EXPECT().
-		GetOnDiskAbsolutePackageFilePath(testNixFlakeLocator).
+		GetOnDiskAbsolutePackageFilePath(testNixFlakeAbsoluteLocator).
 		Times(1).
 		Return(testOnDiskNixFlakePath, nil)
 
 	suite.packageContentProvider.EXPECT().
-		GetOnDiskAbsolutePath(testBuildContextLocator).
+		GetOnDiskAbsolutePath(testBuildContextAbsoluteLocator).
 		Times(1).
 		Return(testOnDiskContextDirPath, nil)
 
diff --git a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/read_file_framework_test.go b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/read_file_framework_test.go
index 924dde177b..b9f1b383f0 100644
--- a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/read_file_framework_test.go
+++ b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/read_file_framework_test.go
@@ -19,7 +19,7 @@ type readFileTestCase struct {
 
 func (suite *KurtosisHelperTestSuite) TestReadFile() {
 	suite.packageContentProvider.EXPECT().GetAbsoluteLocator(testModulePackageId, startosis_constants.PackageIdPlaceholderForStandaloneScript, testModuleRelativeLocator, testNoPackageReplaceOptions).Return(testModuleAbsoluteLocator, nil)
-	suite.packageContentProvider.EXPECT().GetModuleContents(testModuleFileName).Return("Hello World!", nil)
+	suite.packageContentProvider.EXPECT().GetModuleContents(testModuleAbsoluteLocator).Return("Hello World!", nil)
 
 	suite.run(&readFileTestCase{
 		T:                      suite.T(),
@@ -41,6 +41,6 @@ func (t *readFileTestCase) GetStarlarkCodeForAssertion() string {
 
 func (t *readFileTestCase) Assert(result starlark.Value) {
 	t.packageContentProvider.AssertCalled(t, "GetAbsoluteLocator", testModulePackageId, startosis_constants.PackageIdPlaceholderForStandaloneScript, testModuleRelativeLocator, testNoPackageReplaceOptions)
-	t.packageContentProvider.AssertCalled(t, "GetModuleContents", testModuleFileName)
+	t.packageContentProvider.AssertCalled(t, "GetModuleContents", testModuleAbsoluteLocator)
 	require.Equal(t, result, starlark.String("Hello World!"))
 }
diff --git a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/service_config_image_build_spec_test.go b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/service_config_image_build_spec_test.go
index 64740547f7..3d38850ac4 100644
--- a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/service_config_image_build_spec_test.go
+++ b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/service_config_image_build_spec_test.go
@@ -24,10 +24,10 @@ func (suite *KurtosisTypeConstructorTestSuite) TestServiceConfigWithImageBuildSp
 	suite.packageContentProvider.EXPECT().
 		GetAbsoluteLocator(testModulePackageId, testModuleMainFileLocator, testBuildContextDir, testNoPackageReplaceOptions).
 		Times(1).
-		Return(testBuildContextLocator, nil)
+		Return(testModulePackageAbsoluteLocator, nil)
 
 	suite.packageContentProvider.EXPECT().
-		GetOnDiskAbsolutePackageFilePath(testContainerImageLocator).
+		GetOnDiskAbsolutePackageFilePath(testContainerImageAbsoluteLocator).
 		Times(1).
 		Return(testOnDiskContainerImagePath, nil)
 
diff --git a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/static_constants.go b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/static_constants.go
index ed9a08288e..8e5144597a 100644
--- a/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/static_constants.go
+++ b/core/server/api_container/server/startosis_engine/kurtosis_starlark_framework/test_engine/static_constants.go
@@ -22,25 +22,26 @@ var (
 
 	testSrcPath = "/path/to/file.txt"
 
-	testModulePackageId       = "github.com/kurtosistech/test-package"
-	testModuleMainFileLocator = "github.com/kurtosistech/test-package/main.star"
-	testModuleFileName        = "github.com/kurtosistech/test-package/helpers.star"
-	testModuleRelativeLocator = "./helpers.star"
+	testModulePackageId              = "github.com/kurtosistech/test-package"
+	testModulePackageAbsoluteLocator = startosis_packages.NewPackageAbsoluteLocator(testModulePackageId, "")
+	testModuleMainFileLocator        = "github.com/kurtosistech/test-package/main.star"
+	testModuleFileName               = "github.com/kurtosistech/test-package/helpers.star"
+	testModuleRelativeLocator        = "./helpers.star"
 
 	testModuleAbsoluteLocator = startosis_packages.NewPackageAbsoluteLocator(testModuleFileName, "")
 
 	emptyAbsoluteLocator = startosis_packages.NewPackageAbsoluteLocator("", "")
 
-	testContainerImageName                    = "kurtosistech/example-datastore-server"
-	testBuildContextDir                       = "./"
-	testBuildFile                             = "foo.Dockerfile"
-	testTargetStage                           = "builder"
-	testBuildContextLocator                   = testModulePackageId
-	testContainerImageLocator                 = "github.com/kurtosistech/test-package/Dockerfile"
-	testContainerImageLocatorWithBuildFile    = "github.com/kurtosistech/test-package/foo.Dockerfile"
-	testOnDiskContextDirPath                  = "kurtosis-data/test-package"
-	testOnDiskContainerImagePath              = "kurtosis-data/test-package/Dockerfile"
-	testOnDiskContainerImagePathWithBuildFile = "kurtosis-data/test-package/foo.Dockerfile"
+	testContainerImageName                         = "kurtosistech/example-datastore-server"
+	testBuildContextDir                            = "./"
+	testBuildFile                                  = "foo.Dockerfile"
+	testTargetStage                                = "builder"
+	testBuildContextAbsoluteLocator                = startosis_packages.NewPackageAbsoluteLocator(testModulePackageId, "")
+	testContainerImageAbsoluteLocator              = startosis_packages.NewPackageAbsoluteLocator("github.com/kurtosistech/test-package/Dockerfile", "")
+	testContainerImageAbsoluteLocatorWithBuildFile = startosis_packages.NewPackageAbsoluteLocator("github.com/kurtosistech/test-package/foo.Dockerfile", "")
+	testOnDiskContextDirPath                       = "kurtosis-data/test-package"
+	testOnDiskContainerImagePath                   = "kurtosis-data/test-package/Dockerfile"
+	testOnDiskContainerImagePathWithBuildFile      = "kurtosis-data/test-package/foo.Dockerfile"
 
 	testNixContextDir           = "./"
 	testNixImageName            = "test-image"
@@ -49,7 +50,7 @@ var (
 	testOnDiskNixContextDirPath = "kurtosis-data/test-package"
 	testOnDiskNixFlakePath      = "kurtosis-data/test-package/server/app/flake.nix"
 	testOnDiskNixFlakeDir       = "kurtosis-data/test-package/server/app"
-	testNixFlakeLocator         = "github.com/kurtosistech/test-package/server/app/flake.nix"
+	testNixFlakeAbsoluteLocator = startosis_packages.NewPackageAbsoluteLocator("github.com/kurtosistech/test-package/server/app/flake.nix", "")
 
 	testRegistryAddr     = "http://registry.test.io"
 	testRegistryUsername = "kurtosis"
diff --git a/core/server/api_container/server/startosis_engine/kurtosis_types/service_config/image_build_spec.go b/core/server/api_container/server/startosis_engine/kurtosis_types/service_config/image_build_spec.go
index 5899ae4817..0f868de429 100644
--- a/core/server/api_container/server/startosis_engine/kurtosis_types/service_config/image_build_spec.go
+++ b/core/server/api_container/server/startosis_engine/kurtosis_types/service_config/image_build_spec.go
@@ -205,7 +205,7 @@ func getOnDiskImageBuildSpecPaths(
 	// get on disk directory path of Dockerfile
 	containerImageAbsoluteLocatorStr := path.Join(contextDirAbsoluteLocator.GetLocator(), defaultContainerImageFileName)
 	if buildFile != "" {
-		containerImageAbsoluteLocatorStr = path.Join(containerImageAbsoluteLocatorStr, buildFile)
+		containerImageAbsoluteLocatorStr = path.Join(contextDirAbsoluteLocator.GetLocator(), buildFile)
 	}
 
 	containerImageAbsoluteLocator := startosis_packages.NewPackageAbsoluteLocator(containerImageAbsoluteLocatorStr, contextDirAbsoluteLocator.GetTagBranchOrCommit())