terraform test: allow providers in test files to reference variables

internal/backend/local/backend_local.go

@@ -508,20 +508,23 @@ func (v unparsedUnknownVariableValue) ParseVariableValue(mode configs.VariablePa
 }
 
 type unparsedTestVariableValue struct {
-	expr hcl.Expression
-	ctx  *hcl.EvalContext
+	Expr hcl.Expression
 }
 
+var _ backend.UnparsedVariableValue = unparsedTestVariableValue{}
+
 func (v unparsedTestVariableValue) ParseVariableValue(mode configs.VariableParsingMode) (*terraform.InputValue, tfdiags.Diagnostics) {
 	var diags tfdiags.Diagnostics
-	val, hclDiags := v.expr.Value(v.ctx) // nil because no function calls or variable references are allowed here
-	diags = diags.Append(hclDiags)
 
-	rng := tfdiags.SourceRangeFromHCL(v.expr.Range())
+	value, valueDiags := v.Expr.Value(nil)
+	diags = diags.Append(valueDiags)
+	if valueDiags.HasErrors() {
+		return nil, diags
+	}
 
 	return &terraform.InputValue{
-		Value:       val,
-		SourceType:  terraform.ValueFromConfig, // Test variables always come from config.
-		SourceRange: rng,
+		Value:       value,
+		SourceType:  terraform.ValueFromConfig,
+		SourceRange: tfdiags.SourceRangeFromHCL(v.Expr.Range()),
 	}, diags
 }

internal/command/test_test.go

@@ -163,6 +163,14 @@ func TestTest(t *testing.T) {
 			args:     []string{"-var=global=\"triple\""},
 			code:     0,
 		},
+		"unreferenced_global_variable": {
+			override: "variable_references",
+			expected: "2 passed, 0 failed.",
+			// The other variable shouldn't pass validation, but it won't be
+			// referenced anywhere so should just be ignored.
+			args: []string{"-var=global=\"triple\"", "-var=other=bad"},
+			code: 0,
+		},
 		"variables_types": {
 			expected: "1 passed, 0 failed.",
 			args:     []string{"-var=number_input=0", "-var=string_input=Hello, world!", "-var=list_input=[\"Hello\",\"world\"]"},
@@ -1184,6 +1192,98 @@ the current run block.
 	}
 }
 
+func TestTest_UndefinedVariables(t *testing.T) {
+	td := t.TempDir()
+	testCopyDir(t, testFixturePath(path.Join("test", "variables_undefined_in_config")), td)
+	defer testChdir(t, td)()
+
+	provider := testing_command.NewProvider(nil)
+	view, done := testView(t)
+
+	c := &TestCommand{
+		Meta: Meta{
+			testingOverrides: metaOverridesForProvider(provider.Provider),
+			View:             view,
+		},
+	}
+
+	code := c.Run([]string{"-no-color"})
+	output := done(t)
+
+	if code == 0 {
+		t.Errorf("expected status code 0 but got %d", code)
+	}
+
+	expectedOut := `main.tftest.hcl... in progress
+  run "test"... fail
+main.tftest.hcl... tearing down
+main.tftest.hcl... fail
+
+Failure! 0 passed, 1 failed.
+`
+	actualOut := output.Stdout()
+	if diff := cmp.Diff(actualOut, expectedOut); len(diff) > 0 {
+		t.Errorf("output didn't match expected:\nexpected:\n%s\nactual:\n%s\ndiff:\n%s", expectedOut, actualOut, diff)
+	}
+
+	expectedErr := `
+Error: Reference to undeclared input variable
+
+  on main.tf line 2, in resource "test_resource" "foo":
+   2:   value = var.input
+
+An input variable with the name "input" has not been declared. This variable
+can be declared with a variable "input" {} block.
+`
+	actualErr := output.Stderr()
+	if diff := cmp.Diff(actualErr, expectedErr); len(diff) > 0 {
+		t.Errorf("output didn't match expected:\nexpected:\n%s\nactual:\n%s\ndiff:\n%s", expectedErr, actualErr, diff)
+	}
+
+	if provider.ResourceCount() > 0 {
+		t.Errorf("should have deleted all resources on completion but left %v", provider.ResourceString())
+	}
+}
+
+func TestTest_VariablesInProviders(t *testing.T) {
+	td := t.TempDir()
+	testCopyDir(t, testFixturePath(path.Join("test", "provider_vars")), td)
+	defer testChdir(t, td)()
+
+	provider := testing_command.NewProvider(nil)
+	view, done := testView(t)
+
+	c := &TestCommand{
+		Meta: Meta{
+			testingOverrides: metaOverridesForProvider(provider.Provider),
+			View:             view,
+		},
+	}
+
+	code := c.Run([]string{"-no-color"})
+	output := done(t)
+
+	if code != 0 {
+		t.Errorf("expected status code 0 but got %d", code)
+	}
+
+	expected := `main.tftest.hcl... in progress
+  run "test"... pass
+main.tftest.hcl... tearing down
+main.tftest.hcl... pass
+
+Success! 1 passed, 0 failed.
+`
+	actual := output.All()
+	if diff := cmp.Diff(actual, expected); len(diff) > 0 {
+		t.Errorf("output didn't match expected:\nexpected:\n%s\nactual:\n%s\ndiff:\n%s", expected, actual, diff)
+	}
+
+	if provider.ResourceCount() > 0 {
+		t.Errorf("should have deleted all resources on completion but left %v", provider.ResourceString())
+	}
+}
+
 func TestTest_ExpectedFailuresDuringPlanning(t *testing.T) {
 	td := t.TempDir()
 	testCopyDir(t, testFixturePath(path.Join("test", "expected_failures_during_planning")), td)

internal/command/testdata/test/provider_vars/main.tf

@@ -0,0 +1,9 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}
+
+resource "test_resource" "foo" {}

internal/command/testdata/test/provider_vars/main.tftest.hcl

@@ -0,0 +1,10 @@
+
+variables {
+  resource_directory = "my-resource-dir"
+}
+
+provider "test" {
+  resource_prefix = var.resource_directory
+}
+
+run "test" {}

internal/command/testdata/test/variables_undefined_in_config/main.tf

@@ -0,0 +1,3 @@
+resource "test_resource" "foo" {
+  value = var.input
+}

internal/command/testdata/test/variables_undefined_in_config/main.tftest.hcl

@@ -0,0 +1,10 @@
+run "test" {
+  variables {
+    input = "value"
+  }
+
+  assert {
+    condition = test_resource.foo.value == "value"
+    error_message = "bad value"
+  }
+}

internal/configs/config.go

@@ -854,94 +854,3 @@ func (c *Config) CheckCoreVersionRequirements() hcl.Diagnostics {
 
 	return diags
 }
-
-// TransformForTest prepares the config to execute the given test.
-//
-// This function directly edits the config that is to be tested, and returns a
-// function that will reset the config back to its original state.
-//
-// Tests will call this before they execute, and then call the deferred function
-// to reset the config before the next test.
-func (c *Config) TransformForTest(run *TestRun, file *TestFile) (func(), hcl.Diagnostics) {
-	var diags hcl.Diagnostics
-
-	// Currently, we only need to override the provider settings.
-	//
-	// We can have a set of providers defined within the config, we can also
-	// have a set of providers defined within the test file. Then the run can
-	// also specify a set of overrides that tell Terraform exactly which
-	// providers from the test file to apply into the config.
-	//
-	// The process here is as follows:
-	//   1. Take all the providers in the original config keyed by name.alias,
-	//      we call this `previous`
-	//   2. Copy them all into a new map, we call this `next`.
-	//   3a. If the run has configuration specifying provider overrides, we copy
-	//       only the specified providers from the test file into `next`. While
-	//       doing this we ensure to preserve the name and alias from the
-	//       original config.
-	//   3b. If the run has no override configuration, we copy all the providers
-	//       from the test file into `next`, overriding all providers with name
-	//       collisions from the original config.
-	//   4. We then modify the original configuration so that the providers it
-	//      holds are the combination specified by the original config, the test
-	//      file and the run file.
-	//   5. We then return a function that resets the original config back to
-	//      its original state. This can be called by the surrounding test once
-	//      completed so future run blocks can safely execute.
-
-	// First, initialise `previous` and `next`. `previous` contains a backup of
-	// the providers from the original config. `next` contains the set of
-	// providers that will be used by the test. `next` starts with the set of
-	// providers from the original config.
-	previous := c.Module.ProviderConfigs
-	next := make(map[string]*Provider)
-	for key, value := range previous {
-		next[key] = value
-	}
-
-	if run != nil && len(run.Providers) > 0 {
-		// Then we'll only copy over and overwrite the specific providers asked
-		// for by this run block.
-
-		for _, ref := range run.Providers {
-
-			testProvider, ok := file.Providers[ref.InParent.String()]
-			if !ok {
-				// Then this reference was invalid as we didn't have the
-				// specified provider in the parent. This should have been
-				// caught earlier in validation anyway so is unlikely to happen.
-				diags = append(diags, &hcl.Diagnostic{
-					Severity: hcl.DiagError,
-					Summary:  fmt.Sprintf("Missing provider definition for %s", ref.InParent.String()),
-					Detail:   "This provider block references a provider definition that does not exist.",
-					Subject:  ref.InParent.NameRange.Ptr(),
-				})
-				continue
-			}
-
-			next[ref.InChild.String()] = &Provider{
-				Name:       ref.InChild.Name,
-				NameRange:  ref.InChild.NameRange,
-				Alias:      ref.InChild.Alias,
-				AliasRange: ref.InChild.AliasRange,
-				Version:    testProvider.Version,
-				Config:     testProvider.Config,
-				DeclRange:  testProvider.DeclRange,
-			}
-
-		}
-	} else {
-		// Otherwise, let's copy over and overwrite all providers specified by
-		// the test file itself.
-		for key, provider := range file.Providers {
-			next[key] = provider
-		}
-	}
-
-	c.Module.ProviderConfigs = next
-	return func() {
-		// Reset the original config within the returned function.
-		c.Module.ProviderConfigs = previous
-	}, diags
-}