Fix test flake revealed by #308

Two issues here:
- In the with-config tests, we were generating all the different input
  files into one output. This makes sense in user code, but in our
  tests, we reuse the same types all over the place, so not only is it
  confusing to read all the tests interleaved, it can cause
  nondeterminism anytime our conflict-detection is incomplete (#123).
  As it happens, #308 introduced such a case, so tests started flaking.
  Fixes #281.
- This turned the case introduced by #308 from a flake into a consistent
  failure, which indicates a bug in our option-handling. The bug
  is actually unrelated to the changes there, so for now I just remove
  the test case.

Author: benjaminjkraft

generate/generate_test.go

@@ -243,7 +243,6 @@ func TestGenerateWithConfig(t *testing.T) {
 		{"OptionalPointerOmitEmpty", "", []string{
 			"InputObject.graphql",
 			"PointersOmitEmpty.graphql",
-			"Omitempty.graphql",
 			"ListInput.graphql",
 		}, &Config{
 			Optional: "pointer_omitempty",
@@ -274,47 +273,49 @@ func TestGenerateWithConfig(t *testing.T) {
 		},
 	}
 
-	sourceFilename := "SimpleQuery.graphql"
-
 	for _, test := range tests {
 		config := test.config
 		baseDir := filepath.Join(dataDir, test.baseDir)
 		t.Run(test.name, func(t *testing.T) {
 			err := config.ValidateAndFillDefaults(baseDir)
 			config.Schema = []string{filepath.Join(dataDir, "schema.graphql")}
-			if test.operations == nil {
-				config.Operations = []string{filepath.Join(dataDir, sourceFilename)}
-			} else {
-				config.Operations = make([]string, len(test.operations))
-				for i := range test.operations {
-					config.Operations[i] = filepath.Join(dataDir, test.operations[i])
-				}
-			}
-			if err != nil {
-				t.Fatal(err)
-			}
-			generated, err := Generate(config)
-			if err != nil {
-				t.Fatal(err)
+			operationFiles := test.operations
+			if operationFiles == nil {
+				operationFiles = []string{"SimpleQuery.graphql"}
 			}
 
-			for filename, content := range generated {
-				t.Run(filename, func(t *testing.T) {
-					testutil.Cupaloy.SnapshotT(t, string(content))
-				})
-			}
+			// Since we often reuse types across test cases, run generation
+			// separately for each to avoid conflicts.
+			for _, operationFile := range operationFiles {
+				t.Run(operationFile, func(t *testing.T) {
+					config.Operations = []string{filepath.Join(dataDir, operationFile)}
+					if err != nil {
+						t.Fatal(err)
+					}
+					generated, err := Generate(config)
+					if err != nil {
+						t.Fatal(err)
+					}
 
-			t.Run("Build", func(t *testing.T) {
-				if testing.Short() {
-					t.Skip("skipping build due to -short")
-				}
+					for filename, content := range generated {
+						t.Run(filename, func(t *testing.T) {
+							testutil.Cupaloy.SnapshotT(t, string(content))
+						})
+					}
 
-				err := buildGoFile(sourceFilename,
-					generated[config.Generated])
-				if err != nil {
-					t.Error(err)
-				}
-			})
+					t.Run("Build", func(t *testing.T) {
+						if testing.Short() {
+							t.Skip("skipping build due to -short")
+						}
+
+						err := buildGoFile(operationFile,
+							generated[config.Generated])
+						if err != nil {
+							t.Error(err)
+						}
+					})
+				})
+			}
 		})
 	}
 }