feat(blocks): adds validation_warnings data source

Adds a validation_warnings data source, which accepts a list of at least one warning{} block. The
warning schema is identical to the validation_warning resource and data source schema.

See #1

docs/data-sources/warnings.md

@@ -0,0 +1,36 @@
+---
+# generated by https://github.com/hashicorp/terraform-plugin-docs
+page_title: "validation_warnings Data Source - terraform-provider-validation"
+subcategory: ""
+description: |-
+  Causes one or more warnings to be shown if the condition is true.
+---
+
+# validation_warnings (Data Source)
+
+Causes one or more warnings to be shown if the condition is true.
+
+
+
+<!-- schema generated by tfplugindocs -->
+## Schema
+
+### Required
+
+- `warning` (Block List, Min: 1) (see [below for nested schema](#nestedblock--warning))
+
+### Read-Only
+
+- `id` (String) The ID of this resource.
+
+<a id="nestedblock--warning"></a>
+### Nested Schema for `warning`
+
+Required:
+
+- `condition` (Boolean) The condition which, if true, causes a warning message to be printed.
+- `summary` (String) The message displayed to the user if the condition is true.
+
+Optional:
+
+- `details` (String) More details about the message being displayed to the user, if any.

validation/data_source_warnings.go

@@ -0,0 +1,31 @@
+package validation
+
+import (
+	"context"
+
+	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+)
+
+func dataSourceWarnings() *schema.Resource {
+	return &schema.Resource{
+		Description: "Causes one or more warnings to be shown if the condition is true.",
+		ReadContext: dataSourceWarningsRead,
+		Schema: map[string]*schema.Schema{
+			"warning": {
+				Type: schema.TypeList,
+				Elem: &schema.Resource{
+					Schema: warnDataSchema,
+				},
+				Required: true,
+			},
+		},
+	}
+}
+
+func dataSourceWarningsRead(ctx context.Context, data *schema.ResourceData, i interface{}) diag.Diagnostics {
+	data.SetId("none")
+	warnings := data.Get("warning")
+	warnList := warnings.([]interface{})
+	return parseWarnings(warnList)
+}

validation/data_source_warnings_test.go

@@ -0,0 +1,54 @@
+package validation
+
+import (
+	"bytes"
+	"testing"
+	"text/template"
+
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
+)
+
+const dataSrcWarns = "data.validation_warnings.warns"
+
+func TestDataSourceWarningsBasic(t *testing.T) {
+	vs := []testValidation{
+		{Condition: true, Summary: "summary"},
+		{Condition: true, Summary: "Summary2", Details: "with details"},
+		{},
+	}
+
+	resource.Test(t, resource.TestCase{
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccDataValidationWarningsConfig(t, vs),
+				Check:  resource.ComposeTestCheckFunc(testAccCheckResourceExists(dataSrcWarns)),
+			},
+		},
+	})
+}
+
+func testAccDataValidationWarningsConfig(t *testing.T, v []testValidation) string {
+	t.Helper()
+
+	rsc := `data "validation_warnings" "warns" {
+	{{- range . }}
+	warning {
+		condition = {{ .Condition }}
+		summary   = "{{ .Summary }}"
+		{{ if .Details }}details   = "{{ .Details }}"{{ end }}
+	}
+	{{ end }}
+}
+`
+
+	tmpl := template.New("test")
+	out := &bytes.Buffer{}
+	parsed, _ := tmpl.Parse(rsc)
+
+	if err := parsed.Execute(out, v); err != nil {
+		t.Error(err)
+	}
+
+	return out.String()
+}

validation/provider.go

@@ -36,9 +36,10 @@ func Provider() *schema.Provider {
 			"validation_warnings": resourceWarnings(),
 		},
 		DataSourcesMap: map[string]*schema.Resource{
-			"validation_error":   dataSourceError(),
-			"validation_errors":  dataSourceErrors(),
-			"validation_warning": dataSourceWarning(),
+			"validation_error":    dataSourceError(),
+			"validation_errors":   dataSourceErrors(),
+			"validation_warning":  dataSourceWarning(),
+			"validation_warnings": dataSourceWarnings(),
 		},
 	}
 }