Handle NoSuchKeyException in exception handling and add related integration tests

- Added a handler for `NoSuchKeyException` to return a NOT_FOUND response with appropriate details.
- Introduced integration tests to validate behavior when accessing non-existent workspace files.

Author: jreynard-code

api/src/integrationTest/kotlin/com/cosmotech/api/home/workspace/WorkspaceControllerTests.kt

@@ -34,6 +34,7 @@ import org.springframework.security.test.web.servlet.request.SecurityMockMvcRequ
 import org.springframework.test.context.ActiveProfiles
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*
 import org.springframework.test.web.servlet.result.MockMvcResultHandlers
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers.content
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers.status
 
@@ -658,4 +659,40 @@ class WorkspaceControllerTests : ControllerTestBase() {
             document(
                 "organizations/{organization_id}/workspaces/{workspace_id}/files/download/GET"))
   }
+
+  @Test
+  @WithMockOauth2User
+  fun `download workspace file with wrong file name`() {
+
+    val workspaceId =
+        createWorkspaceAndReturnId(
+            mvc, organizationId, constructWorkspaceCreateRequest(solutionId = solutionId))
+
+    val fileName = "test.txt"
+    val fileToUpload =
+        this::class.java.getResourceAsStream("/workspace/$fileName")
+            ?: throw IllegalStateException(
+                "$fileName file used for organizations/{organization_id}/workspaces/{workspace_id}/files/POST endpoint documentation cannot be null")
+
+    val mockFile =
+        MockMultipartFile(
+            "file", fileName, MediaType.TEXT_PLAIN_VALUE, IOUtils.toByteArray(fileToUpload))
+
+    val destination = "path/to/a/directory/"
+    mvc.perform(
+        multipart("/organizations/$organizationId/workspaces/$workspaceId/files")
+            .file(mockFile)
+            .param("overwrite", "true")
+            .param("destination", destination)
+            .accept(MediaType.APPLICATION_JSON)
+            .with(csrf()))
+
+    mvc.perform(
+            get("/organizations/$organizationId/workspaces/$workspaceId/files/download")
+                .param("file_name", "Wrong file name")
+                .accept(MediaType.APPLICATION_OCTET_STREAM))
+        .andExpect(status().is4xxClientError)
+        .andExpect(jsonPath("$.detail").value("The specified key does not exist."))
+        .andDo(MockMvcResultHandlers.print())
+  }
 }

common/src/main/kotlin/com/cosmotech/common/exceptions/CsmExceptionHandling.kt

@@ -21,6 +21,7 @@ import org.springframework.web.bind.annotation.RestControllerAdvice
 import org.springframework.web.context.request.WebRequest
 import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler
 import org.springframework.web.util.BindErrorUtils
+import software.amazon.awssdk.services.s3.model.NoSuchKeyException
 
 @Order(Ordered.HIGHEST_PRECEDENCE)
 @RestControllerAdvice
@@ -160,4 +161,15 @@ open class CsmExceptionHandling : ResponseEntityExceptionHandler() {
     }
     return response
   }
+
+  @ExceptionHandler(NoSuchKeyException::class)
+  fun handleNoSuchKeyException(exception: NoSuchKeyException): ProblemDetail {
+    val response = ProblemDetail.forStatus(HttpStatus.NOT_FOUND)
+    val notImplementedErrorStatus = HttpStatus.NOT_FOUND
+    response.type = URI.create(httpStatusCodeTypePrefix + notImplementedErrorStatus.value())
+    if (exception.awsErrorDetails().errorMessage() != null) {
+      response.detail = exception.awsErrorDetails().errorMessage()
+    }
+    return response
+  }
 }

workspace/src/integrationTest/kotlin/com/cosmotech/workspace/service/WorkspaceServiceIntegrationTest.kt

@@ -177,6 +177,24 @@ class WorkspaceServiceIntegrationTest : CsmTestBase() {
     assertEquals(expectedText, retrievedText)
   }
 
+  @Test
+  fun `test get workspace file with wrong name`() {
+    val resourceTestFile = resourceLoader.getResource("classpath:/$fileName").file
+    val input = FileInputStream(resourceTestFile)
+    val multipartFile =
+        MockMultipartFile(
+            "file", resourceTestFile.getName(), "text/plain", IOUtils.toByteArray(input))
+    workspaceApiService.createWorkspaceFile(
+        organizationSaved.id, workspaceSaved.id, multipartFile, true, null)
+
+    val exception =
+        assertThrows<NoSuchKeyException> {
+          workspaceApiService.getWorkspaceFile(organizationSaved.id, workspaceSaved.id, "WrongName")
+        }
+
+    assertEquals("The specified key does not exist.", exception.awsErrorDetails().errorMessage())
+  }
+
   @Test
   fun `test list workspace files`() {
     every { getCurrentAuthenticatedRoles(any()) } returns listOf("Platform.Admin")