Extract and use `SimpleCargoProject`.

plugin/src/test/groovy/com/nishtahir/CargoBuildTest.groovy

@@ -20,26 +20,10 @@ class CargoBuildTest extends AbstractTest {
                 .build()
                 .writeProject()
 
-        def cargoModule = this.class.classLoader.getResource("rust/Cargo.toml").path
-        cargoModule = new File(cargoModule).parent
-
-        file('app/build.gradle') << """
-            cargo {
-                module = "${cargoModule}"
-                targetDirectory = "${cargoModule}/../target"
-                targets = ["x86_64"]
-                libname = "rust"
-            }
-        """.stripIndent()
-
-        file('library/build.gradle') << """
-            cargo {
-                module = "${cargoModule}"
-                targetDirectory = "${cargoModule}/../target"
-                targets = ["x86_64"]
-                libname = "rust"
-            }
-        """.stripIndent()
+        SimpleCargoProject.builder(temporaryFolder.root)
+            .withTargets(["x86_64"])
+            .build()
+            .writeProject()
 
         when:
         BuildResult buildResult = withGradleVersion(gradleVersion.version)

plugin/src/test/groovy/com/nishtahir/SimpleCargoProject.groovy

@@ -0,0 +1,67 @@
+package com.nishtahir
+
+class SimpleCargoProject {
+    File projectDir
+    List<String> targets
+
+    SimpleCargoProject(File projectDir, List<String> targets) {
+        this.projectDir = projectDir
+        this.targets = targets
+    }
+
+    static class Builder {
+        File projectDir
+        List<String> targets
+
+        Builder(File projectDir) {
+            this.projectDir = projectDir
+        }
+
+        def withTargets(targets) {
+            this.targets = targets
+            return this
+        }
+
+        def build() {
+            if (targets.isEmpty()) {
+                throw new IllegalStateException("No targets provided")
+            }
+            return new SimpleCargoProject(this.projectDir, this.targets)
+        }
+    }
+
+    static def builder(File projectDir) {
+        return new Builder(projectDir)
+    }
+
+    def file(String path) {
+        def file = new File(projectDir, path)
+        file.parentFile.mkdirs()
+        return file
+    }
+
+    def writeProject() {
+        def cargoModule = this.class.classLoader.getResource("rust/Cargo.toml").path
+        cargoModule = new File(cargoModule).parent
+
+        def targetStrings = targets.collect({"\"${it}\"" }).join(", ")
+
+        file('app/build.gradle') << """
+                cargo {
+                    module = "${cargoModule}"
+                    targetDirectory = "${cargoModule}/../target"
+                    targets = [${targetStrings}]
+                    libname = "rust"
+                }
+            """.stripIndent()
+
+        file('library/build.gradle') << """
+                cargo {
+                    module = "${cargoModule}"
+                    targetDirectory = "${cargoModule}/../target"
+                    targets = [${targetStrings}]
+                    libname = "rust"
+                }
+            """.stripIndent()
+    }
+}