fix(scenarios): Fix the regex that locates variables to override (#202)

This PR updates the regex used to find exported variables in a scenario
that have more complex declarations (I.E. variables that get values from
sub-shells, variables that are defined on the same line as another,
etc). This PR fixes #199 and tests have been added to ensure that this
issue doesn't arise again.

internal/engine/scenario.go

@@ -68,7 +68,7 @@ func downloadScenarioMarkdown(url string) ([]byte, error) {
 	return body, nil
 }
 
-// Given either a local or remote path to a markdown file, resolve the path to 
+// Given either a local or remote path to a markdown file, resolve the path to
 // the markdown file and return the contents of the file.
 func resolveMarkdownSource(path string) ([]byte, error) {
 	if strings.HasPrefix(path, "https://") || strings.HasPrefix(path, "http://") {
@@ -128,8 +128,9 @@ func CreateScenarioFromMarkdown(
 
 	varsToExport := lib.CopyMap(environmentVariableOverrides)
 	for key, value := range environmentVariableOverrides {
+		environmentVariables[key] = value
 		logging.GlobalLogger.Debugf("Attempting to override %s with %s", key, value)
-		exportRegex := regexp.MustCompile(fmt.Sprintf(`export %s=["']?([a-z-A-Z0-9_]+)["']?`, key))
+		exportRegex := regexp.MustCompile(fmt.Sprintf(`(?m)export %s\s*=\s*(.*?)(;|&&|$)`, key))
 
 		for index, codeBlock := range codeBlocks {
 			matches := exportRegex.FindAllStringSubmatch(codeBlock.Content, -1)
@@ -150,7 +151,7 @@ func CreateScenarioFromMarkdown(
 				oldValue := match[1]
 
 				// Replace the old export with the new export statement
-				newLine := strings.Replace(oldLine, oldValue, value, 1)
+				newLine := strings.Replace(oldLine, oldValue, value+" ", 1)
 				logging.GlobalLogger.Debugf("Replacing '%s' with '%s'", oldLine, newLine)
 
 				// Update the code block with the new export statement

internal/engine/scenario_test.go

@@ -7,6 +7,8 @@ import (
 	"os"
 	"strings"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 // Mock HTTP server for testing downloading markdown from URL
@@ -76,3 +78,99 @@ func TestResolveMarkdownSource(t *testing.T) {
 		}
 	})
 }
+
+func TestVariableOverrides(t *testing.T) {
+	// Test overriding environment variables
+	t.Run("Override a standard variable declaration", func(t *testing.T) {
+		scenario, err := CreateScenarioFromMarkdown(
+			"../../scenarios/testing/variables.md",
+			[]string{"bash"},
+			map[string]string{
+				"MY_VAR": "my_value",
+			},
+		)
+
+		assert.NoError(t, err)
+		assert.Equal(t, "my_value", scenario.Environment["MY_VAR"])
+		assert.Contains(t, scenario.Steps[0].CodeBlocks[0].Content, "export MY_VAR=my_value")
+	})
+
+	t.Run(
+		"Override a variable that is declared on the same line as another variable, separated by &&",
+		func(t *testing.T) {
+			scenario, err := CreateScenarioFromMarkdown(
+				"../../scenarios/testing/variables.md",
+				[]string{"bash"},
+				map[string]string{
+					"NEXT_VAR": "next_value",
+				},
+			)
+
+			assert.NoError(t, err)
+			assert.Equal(t, "next_value", scenario.Environment["NEXT_VAR"])
+			assert.Contains(
+				t,
+				scenario.Steps[1].CodeBlocks[0].Content,
+				`export NEXT_VAR=next_value && export OTHER_VAR="Hello, World!"`,
+			)
+		},
+	)
+
+	t.Run(
+		"Override a variable that is declared on the same line as another variable, separated by ;",
+		func(t *testing.T) {
+			scenario, err := CreateScenarioFromMarkdown(
+				"../../scenarios/testing/variables.md",
+				[]string{"bash"},
+				map[string]string{
+					"THIS_VAR": "this_value",
+					"THAT_VAR": "that_value",
+				},
+			)
+
+			assert.NoError(t, err)
+			assert.Equal(t, "this_value", scenario.Environment["THIS_VAR"])
+			assert.Equal(t, "that_value", scenario.Environment["THAT_VAR"])
+			assert.Contains(
+				t,
+				scenario.Steps[2].CodeBlocks[0].Content,
+				`export THIS_VAR=this_value ; export THAT_VAR=that_value`,
+			)
+		})
+
+	t.Run("Override a variable that has a subshell command as it's value", func(t *testing.T) {
+		scenario, err := CreateScenarioFromMarkdown(
+			"../../scenarios/testing/variables.md",
+			[]string{"bash"},
+			map[string]string{
+				"SUBSHELL_VARIABLE": "subshell_value",
+			},
+		)
+
+		assert.NoError(t, err)
+		assert.Equal(t, "subshell_value", scenario.Environment["SUBSHELL_VARIABLE"])
+		assert.Contains(
+			t,
+			scenario.Steps[3].CodeBlocks[0].Content,
+			`export SUBSHELL_VARIABLE=subshell_value`,
+		)
+	})
+
+	t.Run("Override a variable that references another variable", func(t *testing.T) {
+		scenario, err := CreateScenarioFromMarkdown(
+			"../../scenarios/testing/variables.md",
+			[]string{"bash"},
+			map[string]string{
+				"VAR2": "var2_value",
+			},
+		)
+
+		assert.NoError(t, err)
+		assert.Equal(t, "var2_value", scenario.Environment["VAR2"])
+		assert.Contains(
+			t,
+			scenario.Steps[4].CodeBlocks[0].Content,
+			`export VAR2=var2_value`,
+		)
+	})
+}

scenarios/testing/variables.md

@@ -0,0 +1,37 @@
+# Variable declaration and usage
+
+## Simple declaration
+
+```bash
+export MY_VAR="Hello, World!"
+echo $MY_VAR
+```
+
+## Double variable declaration
+
+```bash
+export NEXT_VAR="Hello" && export OTHER_VAR="Hello, World!"
+echo $NEXT_VAR
+```
+
+## Double declaration with semicolon
+
+```bash
+export THIS_VAR="Hello"; export THAT_VAR="Hello, World!"
+echo $OTHER_VAR
+```
+
+## Declaration with subshell value
+
+```bash
+export SUBSHELL_VARIABLE=$(echo "Hello, World!")
+echo $SUBSHELL_VARIABLE
+```
+
+## Declaration with other variable in value
+
+```bash
+export VAR1="Hello"
+export VAR2="$VAR1, World!"
+echo $VAR2
+```