Add example for dynamic vars (#13)

README.md

@@ -217,6 +217,58 @@ _testdata/sample.json5
 """
 ```
 
+### Dynamic Variables
+
+When data is not known in advance, but can be inferred from previous steps, you can use 
+[dynamic variables](https://github.com/bool64/shared).
+
+Here is an example where value from response of one step is used in request of another step.
+
+```gherkin
+  Scenario: Creating user and making an order
+    When I request HTTP endpoint with method "POST" and URI "/user"
+
+    And I request HTTP endpoint with body
+    """json
+    {"name": "John Doe"}
+    """
+
+    # Undefined variable infers its value from the actual data on first encounter.
+    Then I should have response with body
+    """json5
+    {
+      // Capturing dynamic user id as $user_id variable.
+     "id":"$user_id",
+     "name": "John Doe",
+     // Ignoring other dynamic values.
+     "created_at":"<ignore-diff>","updated_at": "<ignore-diff>"
+    }
+    """
+
+    # Creating an order for that user with $user_id.
+    When I request HTTP endpoint with method "POST" and URI "/order"
+
+    And I request HTTP endpoint with body
+    """json5
+    {
+      // Replacing with the value of a variable captured previously.
+      "user_id": "$user_id",
+      "item_name": "Watermelon"
+    }
+    """
+    # Variable interpolation works also with body from file.
+
+    Then I should have response with body
+    """json5
+    {
+     "id":"<ignore-diff>",
+     "created_at":"<ignore-diff>","updated_at": "<ignore-diff>",
+     "user_id":"$user_id"
+    }
+    """
+```
+
+
 ## Example Feature
 
 ```gherkin

_testdata/Dynamic.feature

@@ -0,0 +1,43 @@
+Feature: Dynamic data is used in steps
+
+  Scenario: Creating user and making an order
+    When I request HTTP endpoint with method "POST" and URI "/user"
+
+    And I request HTTP endpoint with body
+    """json
+    {"name": "John Doe"}
+    """
+
+    # Undefined variable infers its value from the actual data on first encounter.
+    Then I should have response with body
+    """json5
+    {
+      // Capturing dynamic user id as $user_id variable.
+     "id":"$user_id",
+     "name": "John Doe",
+     // Ignoring other dynamic values.
+     "created_at":"<ignore-diff>","updated_at": "<ignore-diff>"
+    }
+    """
+
+    # Creating an order for that user with $user_id.
+    When I request HTTP endpoint with method "POST" and URI "/order"
+
+    And I request HTTP endpoint with body
+    """json5
+    {
+      // Replacing with the value of a variable captured previously.
+      "user_id": "$user_id",
+      "item_name": "Watermelon"
+    }
+    """
+    # Variable interpolation works also with body from file.
+
+    Then I should have response with body
+    """json5
+    {
+     "id":"<ignore-diff>",
+     "created_at":"<ignore-diff>","updated_at": "<ignore-diff>",
+     "user_id":"$user_id"
+    }
+    """

_testdata/External.feature

@@ -8,12 +8,12 @@ Feature: External Services
     And "some-service" response includes header "X-Bar: foo"
 
     And "some-service" responds with status "OK" and body
-    """
+    """json
     {"key":"value"}
     """
 
     Given "another-service" receives "POST" request "/post-something" with body
-    """
+    """json5
     // Could be a JSON5 too.
     {"foo":"bar"}
     """
@@ -23,7 +23,7 @@ Feature: External Services
     And "another-service" request is received several times
 
     And "another-service" responds with status "OK" and body
-    """
+    """json
     {"theFooWas":"bar"}
     """
 
@@ -34,7 +34,7 @@ Feature: External Services
     Given "some-service" receives "GET" request "/ask-for-foo"
 
     And "some-service" responds with status "OK" and body
-    """
+    """json
     "foo"
     """
 

_testdata/Local.feature

@@ -6,7 +6,7 @@ Feature: HTTP Service
     Then I should have response with status "OK"
 
     And I should have response with body
-    """
+    """json
     [
       {"some":"json"}
     ]
@@ -41,7 +41,7 @@ Feature: HTTP Service
     """
 
     Then I should have response with body
-    """
+    """json
     {"status":"ok"}
     """
 
@@ -63,7 +63,7 @@ Feature: HTTP Service
     And I should have other responses with status "Not Found"
 
     And I should have other responses with body
-    """
+    """json
     {"status":"failed"}
     """
 
@@ -73,7 +73,7 @@ Feature: HTTP Service
     When I request HTTP endpoint with method "POST" and URI "/with-json5-body"
 
     And I request HTTP endpoint with body
-    """
+    """json5
     [
       // some test data
       {"some":"json5"}

external.go

@@ -217,7 +217,7 @@ func (e *External) serviceRequestIncludesHeader(service, header, value string) e
 }
 
 func (e *External) serviceReceivesRequestWithBody(service, method, requestURI string, bodyDoc *godog.DocString) error {
-	body, err := loadBody([]byte(bodyDoc.Content))
+	body, err := loadBody([]byte(bodyDoc.Content), e.Vars)
 	if err != nil {
 		return err
 	}
@@ -226,7 +226,7 @@ func (e *External) serviceReceivesRequestWithBody(service, method, requestURI st
 }
 
 func (e *External) serviceReceivesRequestWithBodyFromFile(service, method, requestURI string, filePath *godog.DocString) error {
-	body, err := loadBodyFromFile(filePath.Content)
+	body, err := loadBodyFromFile(filePath.Content, e.Vars)
 	if err != nil {
 		return err
 	}
@@ -356,7 +356,7 @@ func (e *External) serviceResponseIncludesHeader(service, header, value string)
 }
 
 func (e *External) serviceRespondsWithStatusAndBody(service, statusOrCode string, bodyDoc *godog.DocString) error {
-	body, err := loadBody([]byte(bodyDoc.Content))
+	body, err := loadBody([]byte(bodyDoc.Content), e.Vars)
 	if err != nil {
 		return err
 	}
@@ -365,7 +365,7 @@ func (e *External) serviceRespondsWithStatusAndBody(service, statusOrCode string
 }
 
 func (e *External) serviceRespondsWithStatusAndBodyFromFile(service, statusOrCode string, filePath *godog.DocString) error {
-	body, err := loadBodyFromFile(filePath.Content)
+	body, err := loadBodyFromFile(filePath.Content, e.Vars)
 	if err != nil {
 		return err
 	}

go.mod

@@ -7,6 +7,6 @@ require (
 	github.com/bool64/shared v0.1.3
 	github.com/cucumber/godog v0.11.0
 	github.com/stretchr/testify v1.7.0
-	github.com/swaggest/assertjson v1.6.6
+	github.com/swaggest/assertjson v1.6.7
 	github.com/swaggest/rest v0.2.11
 )

go.sum

@@ -239,8 +239,9 @@ github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/subosito/gotenv v1.2.0/go.mod h1:N0PQaV/YGNqwC0u51sEeR/aUtSLEXKX9iv69rRypqCw=
-github.com/swaggest/assertjson v1.6.6 h1:QO//07sfx9KR6h4t/8L+I5qOWUifLnu8gblhFYwkVQM=
 github.com/swaggest/assertjson v1.6.6/go.mod h1:HNfIAKxJJkeDmtrBU01dcWvEFjhghO96gx9Eo4rRjIc=
+github.com/swaggest/assertjson v1.6.7 h1:Sge9pjgXtfgsH8e1oUK+MZRe8N0BlwyNxKww5Uddf8c=
+github.com/swaggest/assertjson v1.6.7/go.mod h1:kYEgSuEhz5pLkx4A086f9voGIrJZJUweLLYpkaNYKQM=
 github.com/swaggest/form/v5 v5.0.1/go.mod h1:vdnaSTze7cxVKhWiCabrfm1YeLwWLpb9P941Gxv4FnA=
 github.com/swaggest/jsonschema-go v0.3.22/go.mod h1:UMMhyRN4FIUjy6ivVycElnWq+C7ql/1+L2R0BG01LkE=
 github.com/swaggest/openapi-go v0.2.12/go.mod h1:vRXsxIkIg851HF0XiIeUQ5L2DMbag2oCpid9CUXRwbo=

local.go

@@ -1,13 +1,16 @@
 package httpdog
 
 import (
+	"bytes"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io/ioutil"
 	"net/http"
 	"strconv"
 	"strings"
 
+	"github.com/bool64/shared"
 	"github.com/cucumber/godog"
 	"github.com/swaggest/assertjson/json5"
 	"github.com/swaggest/rest/resttest"
@@ -21,9 +24,13 @@ func NewLocal(baseURL string) *Local {
 
 	baseURL = strings.TrimRight(baseURL, "/")
 
-	return &Local{
+	l := Local{
 		Client: resttest.NewClient(baseURL),
 	}
+
+	l.JSONComparer.Vars = &shared.Vars{}
+
+	return &l
 }
 
 // Local is step-driven HTTP client for application local HTTP service.
@@ -180,25 +187,40 @@ func (l *Local) iRequestWithMethodAndURI(method, uri string) error {
 	return nil
 }
 
-func loadBodyFromFile(filePath string) ([]byte, error) {
+func loadBodyFromFile(filePath string, vars *shared.Vars) ([]byte, error) {
 	body, err := ioutil.ReadFile(filePath) // nolint:gosec // File inclusion via variable during tests.
 	if err != nil {
 		return nil, err
 	}
 
-	return loadBody(body)
+	return loadBody(body, vars)
 }
 
-func loadBody(body []byte) ([]byte, error) {
+func loadBody(body []byte, vars *shared.Vars) ([]byte, error) {
+	var err error
+
 	if json5.Valid(body) {
-		return json5.Downgrade(body)
+		if body, err = json5.Downgrade(body); err != nil {
+			return nil, fmt.Errorf("failed to downgrade JSON5 to JSON: %w", err)
+		}
+	}
+
+	if vars != nil {
+		for k, v := range vars.GetAll() {
+			jv, err := json.Marshal(v)
+			if err != nil {
+				return nil, fmt.Errorf("failed to marshal var %s (%v): %w", k, v, err)
+			}
+
+			body = bytes.ReplaceAll(body, []byte(`"`+k+`"`), jv)
+		}
 	}
 
 	return body, nil
 }
 
 func (l *Local) iRequestWithBodyFromFile(filePath *godog.DocString) error {
-	body, err := loadBodyFromFile(filePath.Content)
+	body, err := loadBodyFromFile(filePath.Content, l.JSONComparer.Vars)
 
 	if err == nil {
 		l.WithBody(body)
@@ -208,7 +230,7 @@ func (l *Local) iRequestWithBodyFromFile(filePath *godog.DocString) error {
 }
 
 func (l *Local) iRequestWithBody(bodyDoc *godog.DocString) error {
-	body, err := loadBody([]byte(bodyDoc.Content))
+	body, err := loadBody([]byte(bodyDoc.Content), l.JSONComparer.Vars)
 
 	if err == nil {
 		l.WithBody(body)
@@ -281,7 +303,7 @@ func (l *Local) iShouldHaveResponseWithHeader(key, value string) error {
 }
 
 func (l *Local) iShouldHaveResponseWithBody(bodyDoc *godog.DocString) error {
-	body, err := loadBody([]byte(bodyDoc.Content))
+	body, err := loadBody([]byte(bodyDoc.Content), l.JSONComparer.Vars)
 	if err != nil {
 		return err
 	}
@@ -290,7 +312,7 @@ func (l *Local) iShouldHaveResponseWithBody(bodyDoc *godog.DocString) error {
 }
 
 func (l *Local) iShouldHaveResponseWithBodyFromFile(filePath *godog.DocString) error {
-	body, err := loadBodyFromFile(filePath.Content)
+	body, err := loadBodyFromFile(filePath.Content, l.JSONComparer.Vars)
 	if err != nil {
 		return err
 	}
@@ -299,7 +321,7 @@ func (l *Local) iShouldHaveResponseWithBodyFromFile(filePath *godog.DocString) e
 }
 
 func (l *Local) iShouldHaveOtherResponsesWithBody(bodyDoc *godog.DocString) error {
-	body, err := loadBody([]byte(bodyDoc.Content))
+	body, err := loadBody([]byte(bodyDoc.Content), l.JSONComparer.Vars)
 	if err != nil {
 		return err
 	}
@@ -308,7 +330,7 @@ func (l *Local) iShouldHaveOtherResponsesWithBody(bodyDoc *godog.DocString) erro
 }
 
 func (l *Local) iShouldHaveOtherResponsesWithBodyFromFile(filePath *godog.DocString) error {
-	body, err := loadBodyFromFile(filePath.Content)
+	body, err := loadBodyFromFile(filePath.Content, l.JSONComparer.Vars)
 	if err != nil {
 		return err
 	}