feat(tests): add match test

builtins/tests.md

@@ -1,2 +1,13 @@
 ## The `empty` test
-Check if the input is empty. Works on strings, lists and dictionaries.
+
+Check if the input is empty. Works on strings, lists and dictionaries.
+
+## The `match` test
+
+Expects a string holding a regular expression to be passed as an argument to match against the input. Returns `true` if the input matches the expression and `false` otherwise. For example:
+
+```
+{{ "123" is match("^[0-9]+") }}
+```
+
+will evaluate to `True`.

docs/index.md

@@ -1467,8 +1467,19 @@ Classic type casting tests.
 
 
 ### The `empty` test
+
 Check if the input is empty. Works on strings, lists and dictionaries.
 
+### The `match` test
+
+Expects a string holding a regular expression to be passed as an argument to match against the input. Returns `true` if the input matches the expression and `false` otherwise. For example:
+
+```
+{{ "123" is match("^[0-9]+") }}
+```
+
+will evaluate to `True`.
+
 
 
 ## Methods

internal/provider/tests_test.go

@@ -87,4 +87,40 @@ var _ = Context("tests", func() {
 			itShouldFailToRender(terraformCode, "invalid call to test 'empty': True is neither a list, a dict nor a string")
 		})
 	})
+	Context("match", func() {
+		BeforeEach(func() {
+			*template = `{{- input is match("^f(o)+$") -}}`
+		})
+		Context("when the input is a string that matches", func() {
+			BeforeEach(func() {
+				*context = `input = "foo"`
+			})
+			itShouldSetTheExpectedResult(terraformCode, "True")
+		})
+		Context("when the input is a string that does not matches", func() {
+			BeforeEach(func() {
+				*context = `input = "bar"`
+			})
+			itShouldSetTheExpectedResult(terraformCode, "False")
+		})
+		Context("when the argument is not a valid regex", func() {
+			BeforeEach(func() {
+				*context = `input = "foo"`
+				*template = `{{- input is match("{.*[") -}}`
+			})
+			itShouldFailToRender(terraformCode, "failed to compile: {.*\\[: error parsing regexp")
+		})
+		Context("when the input is an error", func() {
+			BeforeEach(func() {
+				*template = `{{- ("thrown" | fail) is match(".*") -}}`
+			})
+			itShouldFailToRender(terraformCode, "thrown")
+		})
+		Context("when the input is invalid", func() {
+			BeforeEach(func() {
+				*context = `input = true`
+			})
+			itShouldFailToRender(terraformCode, "True is not a string")
+		})
+	})
 })

lib/tests.go

@@ -10,6 +10,7 @@ import (
 
 var Tests = exec.NewTestSet(map[string]exec.TestFunction{
 	"empty": testEmpty,
+	"match": testMatch,
 })
 
 func testEmpty(ctx *exec.Context, in *exec.Value, params *exec.VarArgs) (bool, error) {
@@ -22,3 +23,26 @@ func testEmpty(ctx *exec.Context, in *exec.Value, params *exec.VarArgs) (bool, e
 		return in.Len() == 0, nil
 	}
 }
+
+func testMatch(ctx *exec.Context, in *exec.Value, params *exec.VarArgs) (bool, error) {
+	if in.IsError() {
+		return false, errors.New(in.Error())
+	}
+	var (
+		regex string
+	)
+	if err := params.Take(
+		exec.KeywordArgument("regex", exec.AsValue(2), exec.StringArgument(&regex)),
+	); err != nil {
+		return false, exec.AsValue(exec.ErrInvalidCall(err))
+	}
+	if !in.IsString() {
+		return false, exec.AsValue(exec.ErrInvalidCall(fmt.Errorf("%s is not a string", in.String())))
+	}
+	matcher, err := regexp.Compile(regex)
+	if err != nil {
+		return false, exec.AsValue(exec.ErrInvalidCall(fmt.Errorf("failed to compile: %s: %s", regex, err)))
+	}
+
+	return matcher.MatchString(in.String()), nil
+}