pipelines open: add autocomplete when one pipeline (#3258)

## Changes
When there is only one pipeline deployed, it will automatically open
that pipeline without specifying the name

## Why
Autocompletes open command, like in dry-run and run

## Tests
Modified open acceptance test:
- Ran open both specifying the name of the pipeline and without
Follows #3243

Author: alyssa-db

acceptance/pipelines/open/output.txt

@@ -1,12 +1,6 @@
 
-=== no run key specified
->>> [PIPELINES] open
-Error: expected a KEY of the pipeline to open
-
-Exit code: 1
-
 === not deployed yet
->>> [PIPELINES] open test-pipelines-open
+>>> [PIPELINES] open
 Error: pipeline does not have a URL associated with it (has it been deployed?)
 
 Exit code: 1
@@ -19,6 +13,13 @@ Deployment complete!
 
 === Modify PATH so that real open is not run
 === open after deployment. This will fail to open browser and complain, that's ok, we only want the message
+>>> [PIPELINES] open
+Opening browser at [DATABRICKS_URL]/pipelines/[UUID]?o=[NUMID]
+Error: exec: "open": cannot run executable found relative to current directory
+
+Exit code (musterr): 1
+
+=== open with KEY, expect same output as opening without KEY
 >>> [PIPELINES] open test-pipelines-open
 Opening browser at [DATABRICKS_URL]/pipelines/[UUID]?o=[NUMID]
 Error: exec: "open": cannot run executable found relative to current directory

acceptance/pipelines/open/script

@@ -1,13 +1,13 @@
-title "no run key specified"
-errcode trace $PIPELINES open
-
 title "not deployed yet"
-errcode trace $PIPELINES open test-pipelines-open
+errcode trace $PIPELINES open
 
 errcode trace $PIPELINES deploy
 
 title "Modify PATH so that real open is not run"
 export PATH=.:$PATH
 
 title "open after deployment. This will fail to open browser and complain, that's ok, we only want the message"
+musterr trace $PIPELINES open
+
+title "open with KEY, expect same output as opening without KEY"
 musterr trace $PIPELINES open test-pipelines-open

cmd/pipelines/open.go

@@ -41,10 +41,17 @@ func promptOpenArgument(ctx context.Context, b *bundle.Bundle) (string, error) {
 	return key, nil
 }
 
+// When no arguments are specified, auto-selects a pipeline if there's exactly one,
+// otherwise prompts the user to select a pipeline to open.
 func resolveOpenArgument(ctx context.Context, b *bundle.Bundle, args []string) (string, error) {
-	// If no arguments are specified, prompt the user to select the resource to open.
-	if len(args) == 0 && cmdio.IsPromptSupported(ctx) {
-		return promptOpenArgument(ctx, b)
+	if len(args) == 0 {
+		if key := autoSelectSinglePipeline(b); key != "" {
+			return key, nil
+		}
+
+		if cmdio.IsPromptSupported(ctx) {
+			return promptOpenArgument(ctx, b)
+		}
 	}
 
 	if len(args) < 1 {