fix: include providers from test files in lock command

.changes/v1.15/BUG FIXES-20251106-065000.yaml

@@ -0,0 +1,5 @@
+kind: BUG FIXES
+body: 'command: terraform providers lock now includes providers required by test files'
+time: 2025-11-06T06:50:00.000000Z
+custom:
+    Issue: "37841"

internal/command/providers_lock.go

@@ -123,7 +123,7 @@ func (c *ProvidersLockCommand) Run(args []string) int {
 		source = getproviders.NewRegistrySource(c.Services)
 	}
 
-	config, confDiags := c.loadConfig(".")
+	config, confDiags := c.loadConfigWithTests(".", "tests")
 	diags = diags.Append(confDiags)
 	reqs, hclDiags := config.ProviderRequirements()
 	diags = diags.Append(hclDiags)

internal/command/providers_lock_test.go

@@ -66,6 +66,23 @@ provider "registry.terraform.io/hashicorp/test" {
     "h1:invalid",
   ]
 }
+`
+		runProviderLockGenericTest(t, testDirectory, expected)
+	})
+
+	// This test ensures that providers required by test modules are included
+	// in the lock file. This is a regression test for issue #37841.
+	t.Run("with-tests", func(t *testing.T) {
+		testDirectory := "providers-lock/with-tests"
+		expected := `# This file is maintained automatically by "terraform init".
+# Manual edits may be lost in future updates.
+
+provider "registry.terraform.io/hashicorp/test" {
+  version = "1.0.0"
+  hashes = [
+    "h1:7MjN4eFisdTv4tlhXH5hL4QQd39Jy4baPhFxwAd/EFE=",
+  ]
+}
 `
 		runProviderLockGenericTest(t, testDirectory, expected)
 	})

internal/command/testdata/providers-lock/with-tests/main.tf

@@ -0,0 +1,7 @@
+terraform {
+    required_providers {
+        test = {
+            source = "hashicorp/test"
+        }
+    }
+}

internal/command/testdata/providers-lock/with-tests/main.tftest.hcl

@@ -0,0 +1,9 @@
+provider "test" {
+  alias = "runner"
+}
+
+run "test_run" {
+  providers = {
+    test = test.runner
+  }
+}