diff --git a/src/main/scala/seed/artefact/Coursier.scala b/src/main/scala/seed/artefact/Coursier.scala
index 4226054..684037c 100644
--- a/src/main/scala/seed/artefact/Coursier.scala
+++ b/src/main/scala/seed/artefact/Coursier.scala
@@ -126,14 +126,22 @@ object Coursier {
 
   def resolveSubset(resolution: Resolution,
                     deps: Set[Dep],
-                    optionalArtefacts: Boolean): List[(Classifier, Artefact)] =
-    resolution.subset(coursierDependencies(deps))
-      .dependencyArtifacts(
-        Some(
-          overrideClassifiers(
-            sources = optionalArtefacts,
-            javaDoc = optionalArtefacts))
-      ).map(a => (a._2.classifier, a._3)).toList
+                    optionalArtefacts: Boolean): List[(Classifier, Artefact)] = {
+    val result =
+      resolution
+        .subset(coursierDependencies(deps))
+        .dependencyArtifacts(
+          Some(
+            overrideClassifiers(
+              sources = optionalArtefacts,
+              javaDoc = optionalArtefacts)))
+
+    require(deps.forall(d => result.map(_._1.module).exists(m =>
+      m.organization.value == d.organisation &&
+      m.name.value == d.artefact)), "Missing dependencies in artefact resolution")
+
+    result.map(a => (a._2.classifier, a._3)).toList
+  }
 
   def overrideClassifiers(sources: Boolean, javaDoc: Boolean): Seq[Classifier] =
     Seq(Classifier.empty) ++
diff --git a/src/main/scala/seed/generation/Idea.scala b/src/main/scala/seed/generation/Idea.scala
index b0d7826..d24b9d9 100644
--- a/src/main/scala/seed/generation/Idea.scala
+++ b/src/main/scala/seed/generation/Idea.scala
@@ -153,8 +153,8 @@ object Idea {
               collectJsDeps(build, module).map(dep =>
                 ArtefactResolution.dependencyFromDep(
                   dep, JavaScript,
-                  build.project.scalaVersion,
-                  build.project.scalaJsVersion.get)
+                  build.project.scalaJsVersion.get,
+                  build.project.scalaVersion)
               ).toSet,
               optionalArtefacts = true),
             resolvedTestDeps = module.test.toList.flatMap(test =>
@@ -162,8 +162,8 @@ object Idea {
                 collectJsDeps(build, test).map(dep =>
                   ArtefactResolution.dependencyFromDep(
                     dep, JavaScript,
-                    build.project.scalaVersion,
-                    build.project.scalaJsVersion.get)
+                    build.project.scalaJsVersion.get,
+                    build.project.scalaVersion)
                 ).toSet,
                 optionalArtefacts = true)),
             moduleDeps =
@@ -257,8 +257,8 @@ object Idea {
               collectNativeDeps(build, module).map(dep =>
                 ArtefactResolution.dependencyFromDep(
                   dep, Native,
-                  build.project.scalaVersion,
-                  build.project.scalaNativeVersion.get)
+                  build.project.scalaNativeVersion.get,
+                  build.project.scalaVersion)
               ).toSet,
               optionalArtefacts = true),
             resolvedTestDeps = module.test.toList.flatMap(test =>
@@ -266,8 +266,8 @@ object Idea {
                 collectNativeDeps(build, test).map(dep =>
                   ArtefactResolution.dependencyFromDep(
                     dep, Native,
-                    build.project.scalaVersion,
-                    build.project.scalaNativeVersion.get)
+                    build.project.scalaNativeVersion.get,
+                    build.project.scalaVersion)
                 ).toSet,
                 optionalArtefacts = true)),
             moduleDeps =
diff --git a/src/test/scala/seed/artefact/ArtefactResolutionSpec.scala b/src/test/scala/seed/artefact/ArtefactResolutionSpec.scala
new file mode 100644
index 0000000..2d1aa3e
--- /dev/null
+++ b/src/test/scala/seed/artefact/ArtefactResolutionSpec.scala
@@ -0,0 +1,15 @@
+package seed.artefact
+
+import minitest.SimpleTestSuite
+import seed.model.Build.Dep
+import seed.model.Platform.JavaScript
+
+object ArtefactResolutionSpec extends SimpleTestSuite {
+  test("dependencyFromDep()") {
+    val scalaDep = Dep("org.scala-js", "scalajs-dom", "0.9.6")
+    val javaDep = ArtefactResolution.dependencyFromDep(
+      scalaDep, JavaScript, "0.6", "2.12")
+    assertEquals(javaDep,
+      Dep("org.scala-js", "scalajs-dom_sjs0.6_2.12", "0.9.6"))
+  }
+}
diff --git a/src/test/scala/seed/artefact/CoursierSpec.scala b/src/test/scala/seed/artefact/CoursierSpec.scala
new file mode 100644
index 0000000..ab60172
--- /dev/null
+++ b/src/test/scala/seed/artefact/CoursierSpec.scala
@@ -0,0 +1,20 @@
+package seed.artefact
+
+import minitest.SimpleTestSuite
+import seed.model.Build
+import seed.model.Build.Dep
+
+object CoursierSpec extends SimpleTestSuite {
+  test("Resolve dependency") {
+    val dep = Dep("org.scala-js", "scalajs-dom_sjs0.6_2.12", "0.9.6")
+    val resolution = Coursier.resolveAndDownload(Set(dep),
+      Build.Resolvers(), Coursier.DefaultIvyPath,
+      Coursier.DefaultCachePath, optionalArtefacts = true)
+
+    val result =
+      Coursier.localArtefacts(resolution, Set(dep), optionalArtefacts = true)
+    assert(
+      result.exists(_.javaDocJar.nonEmpty) &&
+      result.exists(_.sourcesJar.nonEmpty))
+  }
+}