Introduce gvm bash env builder for convenience in testing.

src/test/groovy/gvm/GvmBashEnvBuilder.groovy

@@ -0,0 +1,129 @@
+package gvm
+
+class GvmBashEnvBuilder {
+
+    final buildScriptDir = "build/testScripts" as File
+
+    //mandatory fields
+    private final File gvmBase
+    private final CurlStub curlStub
+
+    //optional fields with sensible defaults
+    List candidates = ['groovy', 'grails']
+    List availableCandidates = candidates
+    boolean onlineMode = true
+    boolean forcedOfflineMode = false
+    String broadcast = "This is a LIVE broadcast!"
+    String service = "http://localhost:8080"
+    String jdkHome = "/path/to/my/jdk"
+
+    File gvmDir, gvmBinDir, gvmVarDir, gvmSrcDir
+
+    BashEnv bashEnv
+
+    static GvmBashEnvBuilder create(File gvmBase, CurlStub curlStub){
+        new GvmBashEnvBuilder(gvmBase, curlStub)
+    }
+
+    private GvmBashEnvBuilder(File gvmBase, CurlStub curlStub){
+        this.gvmBase = gvmBase
+        this.curlStub = curlStub
+    }
+
+    GvmBashEnvBuilder withCandidates(List candidates){
+        this.candidates = candidates
+        this
+    }
+
+    GvmBashEnvBuilder withAvailableCandidates(List candidates){
+        this.availableCandidates = candidates
+        this
+    }
+
+    GvmBashEnvBuilder withBroadcast(String broadcast){
+        this.broadcast = broadcast
+        this
+    }
+
+    GvmBashEnvBuilder withOnlineMode(boolean onlineMode){
+        this.onlineMode = this.onlineMode
+        this
+    }
+
+    GvmBashEnvBuilder withForcedOfflineMode(boolean forcedOfflineMode){
+        this.forcedOfflineMode = forcedOfflineMode
+        this
+    }
+
+    GvmBashEnvBuilder withService(String service){
+        this.service = service
+        this
+    }
+
+    GvmBashEnvBuilder withJdkHome(String jdkHome){
+        this.jdkHome = jdkHome
+        this
+    }
+
+    BashEnv build() {
+        gvmDir = prepareDirectory(gvmBase, ".gvm")
+        gvmBinDir = prepareDirectory(gvmDir, "bin")
+        gvmVarDir = prepareDirectory(gvmDir, "var")
+        gvmSrcDir = prepareDirectory(gvmDir, "src")
+
+        initializeCandidates(gvmDir, candidates)
+        initializeAvailableCandidates(gvmVarDir, availableCandidates)
+        initializeBroadcast(gvmVarDir, broadcast)
+
+        primeInitScript(gvmBinDir)
+        primeModuleScripts(gvmSrcDir)
+
+        bashEnv = new BashEnv(gvmBase.absolutePath, [
+            GVM_DIR: gvmDir.absolutePath,
+            GVM_ONLINE: onlineMode,
+            GVM_FORCE_OFFLINE: forcedOfflineMode,
+            GVM_SERVICE: service,
+            JAVA_HOME: jdkHome
+        ])
+    }
+
+    private prepareDirectory(File target, String directoryName) {
+        def directory = new File(target, directoryName)
+        directory.mkdirs()
+        directory
+    }
+
+    private initializeCandidates(File folder, List candidates) {
+        candidates.each { candidate ->
+            new File(folder, candidate).mkdirs()
+        }
+    }
+
+    private initializeAvailableCandidates(File folder, List candidates){
+        new File(folder, "candidates") << candidates.join(",")
+    }
+
+    private initializeBroadcast(File targetFolder, String broadcast) {
+        new File(targetFolder, "broadcast") << broadcast
+    }
+
+    private primeInitScript(File targetFolder) {
+        def sourceInitScript = new File(buildScriptDir, 'gvm-init.sh')
+
+        if (!sourceInitScript.exists())
+            throw new IllegalStateException("gvm-init.sh has not been prepared for consumption.")
+
+        def destInitScript = new File(targetFolder, "gvm-init.sh")
+        destInitScript << sourceInitScript.text
+        destInitScript
+    }
+
+    private primeModuleScripts(File targetFolder){
+        for (f in buildScriptDir.listFiles()){
+            if(!(f.name in ['selfupdate.sh', 'install.sh', 'gvm-init.sh'])){
+                new File(targetFolder, f.name) << f.text
+            }
+        }
+    }
+
+}